In the winter of 2018-2019, I completed an internship at America’s Test Kitchen. As a final project, we were challenged to develop a muffin recipe and write a short article in the style of Cook’s Illustrated. Here’s mine!
Mastering “Coffee Shop” Muffins
Imagine this: a cool Sunday morning at a cafe, sipping a cup of your favorite tea or coffee. If you’re like me, you also have a muffin on the table—the kind that is piled high with streusel and filled with bits of fruit. Modern coffee shop-style muffins are wonderful things, but can often be excessive in many ways: dessert-like sweetness, cake-like airiness, and big enough to serve two (or three!).
I decided to bring the classic apple streusel muffin into the kitchen and make a pastry that’s both easy to whip up and worthy of your Sunday morning at home. To do so, I paid key attention to the texture, sweetness, streusel, and the all-important apple.
A Talk About Texture
What sets muffins and cupcakes apart (besides frosting, of course) is the texture or crumb. A good cupcake is light and airy on the inside, whereas muffins tend to have a tighter crumb. This is accomplished largely through mixing. Cakes are often made using the creaming method, which works by beating butter and sugar together to create microscopic pockets of air in the batter, yielding a fluffy crumb.
By using the aptly named muffin method—whisking dry and wet ingredients separately, then gently stirring together—I ensured a muffin with a satisfying bite, fitting for a breakfast pastry. The batter is best when kept a little lumpy. By not mixing the batter until completely smooth, the gluten development is limited, thus guarding the muffins against getting tough or chewy.
Because this method uses a liquid fat—here, melted butter—it is important to make sure all the ingredients for the batter are at room temperature. If the eggs or yogurt are chilled from the refrigerator, they can re-harden the butter and prevent the batter from fully hydrating.
Speaking of yogurt*, it also plays a key role in texture. It is a great option to create moist baked goods because it is largely made up of an emulsion of protein, water, and fat. Keeping the water bound with other molecules helps to prevent drying out during baking, while the fat (even in low-fat yogurt) tenderizes and further adds moisture to the batter.
Lastly, yogurt also adds acidity which provides a trigger for the baking powder that works to provide the “lift” for these muffins, as well as a subtle tang that helps to balance the sweetness.
Sorting Out Sweetness
Another important distinction between cake and muffins is the ratio of sugar with other ingredients. I avoided an overly sweet muffin in order to let other flavors shine—and prevent the feeling of an impending 10 AM sugar crash. To do this, I kept the total amount of sugar below one cup in the batter and used both granulated and dark brown sugar. The extra molasses in the dark brown sugar adds subtle notes of caramel and helps round out any saccharine edge. In addition, it keeps the muffins moist even after baking through its hygroscopic characteristics (the tendency of sugar to attract and absorb moisture from the surrounding air).
By taking a few extra minutes to brown the butter, the muffins gain nuttiness that is complemented by the warm spice of cinnamon and nutmeg. This adds a deep complexity to the autumnal flavors. Less sugar in the batter leaves the opportunity to have a sweeter “pop” of apple and more of everyone’s favorite part of the muffin: the streusel.
The Struggle for Streusel
Whereas many coffee shop-style muffins have a sandy crumble, I wanted to provide this version with a crisp bite and toffee-like flavor. The comforting taste, reminiscent of warm oatmeal cookies, came naturally with the combination of browned butter, brown sugar, and old-fashioned oats. Surprisingly, achieving the crunch in the clusters of streusel is what proved to be the challenge.
I tried various ratios of butter, flour, and sugar but none hit the mark. Streusel that formed moist clumps when mixed ended up with the butter melting down the sides of the muffin during baking and caused greasy bottoms. Streusel that had enough flour to fully soak up the butter ended up powdery and loose. The seemingly counterintuitive solution? Add water.
Adding the melted browned butter to the mixture first helps to coat the gluten strands and keep the streusel chewy on the inside, but stirring in water at the end still allows for the formation of clumps that retained their shape throughout baking. A period of chilling allows the mixture to fully hydrate and further create distinct morsels. During baking, the water in the mixture steams and evaporates, leaving a crispy streusel.
One last obstacle was the issue of how to build beautiful piles of crumble on top of each muffin without having most of it end up on the flats of the muffin tin. By folding squares of parchment into muffin liners with tall, “lotus-style” sides, it allowed the muffins to bake tall and still hold a generous pinch of delicious streusel.
An Assortment of Apples
Even with all the talk of texture and streusel, the real star of these muffins are the apples. I tried five different sweet varieties: Gala, Golden Delicious, Cripps Pink, Braeburn, and dried apples.
After baking, diced Golden Delicious apples seemed to “melt” into the muffin. They exhibited a very soft texture and lackluster fruit flavor. Galas retained a decently firm texture, but again lost much of their flavor. Small pieces of dried apples completely absorbed moisture from the batter and caused the baked muffin to be chewy and dry. Braeburn and Cripps Pink apples were the clear winners, as they both provided pleasant bursts of sweet, ripe apple flavor while maintaining structural integrity. The Braeburn variety just edged out Cripps Pink with its superior apple flavor.
Even after all the testing, I maintain that the best part of these muffins is how they taste the next day. The harmony of browned butter, warm spice, and sweet apple develops even more overnight. So make your Sunday batch, but make sure to save one (or two) for Monday morning.
The slideshow includes a couple of shots from the development process. From my first batch, to streusel struggles, to the final muffin!
Apple Muffins with Browned Butter Oat Streusel
Crisp, sweet apples work best in these muffins. In tests, Braeburn apples yielded the preferred soft-but-distinct texture and fruity apple flavor, but the Cripps Pink apple variety (also called Pink Lady apples) are a good option as well. This recipe also uses parchment squares to create tall muffin liners; they allow for the muffins to bake tall and hold generous piles of streusel. Alternatively, lotus-style muffin liners can also be purchased and used.
Makes 12 muffins
Brown Butter Oat Streusel:
- ¾ cup (3.75 ounces) all-purpose flour
- ¾ cup (2.25 ounces) old-fashioned oats
- ½ cup (3.5 ounces) dark brown sugar
- ¼ teaspoon table salt
- 14 tablespoons unsalted butter
- 2 tablespoons water
- 1 ½ teaspoon vanilla extract
- 2 cups (10 ounces) all-purpose flour
- 2 teaspoons ground cinnamon
- 2 teaspoons baking powder
- ¾ teaspoon baking soda
- ¼ teaspoon ground nutmeg
- ¼ teaspoon table salt
- 2 large eggs, room temperature
- 1 cup plain low-fat yogurt, room temperature*
- ½ cup (3.5 ounces) granulated sugar
- ¼ cup (1.75 ounces) dark brown sugar
- 1 teaspoon vanilla extract
- 12 ounces Braeburn apples, peeled, cored, and cut into ¼-inch pieces (1 ½ cups diced pieces)
- Adjust oven rack to middle position and heat oven to 350 degrees. Cut 12 6-inch squares out of parchment paper. Gently press and crease paper squares into a standard 12-cup muffin tin to create muffin liners with tall, folded walls. Paper may not fully stay in cups until they are filled with muffin batter.
- FOR THE OAT STREUSEL: Stir flour, oats, sugar, and salt together in medium bowl.
- Melt butter in small saucepan over medium-high heat. Continue to cook, stirring frequently, until butter is lightly browned and aromatic, 2 to 3 minutes. Reserve ½ cup butter for muffin mixture and set aside to cool.
- Stir remaining 6 tablespoons browned butter into flour mixture until evenly combined. Add water and vanilla extract and stir until evenly moistened and mixture starts to clump. Cover bowl with plastic wrap and chill for at least 10 minutes, or until ready to use.
- FOR THE APPLE MUFFINS: Whisk flour, cinnamon, baking powder, baking soda, nutmeg, and salt together in a large bowl. In a separate medium bowl, whisk eggs, yogurt, granulated sugar, and brown sugar until no lumps of brown sugar remain. Stir in reserved browned butter and vanilla until smooth, then fold in diced apples.
- Add egg mixture to flour mixture and use a rubber spatula to gently mix, just until no visible flour remains. Batter should be thick and slightly lumpy. Use a level ⅓-cup dry measurement to fill each prepared muffin cup. Use your hands to break apart streusel mixture and crumble evenly over each muffin, breaking up any clumps larger than a marble. Bake until a toothpick inserted into the center of the muffins comes out clean, about 25 to 30 minutes, rotating muffin tin halfway through baking.
- Let cool in tin for at least 1 hour. Cooled muffins can be stored in an airtight container or zipper lock bag at room temperature for up to 3 days.
*UPDATE 7/2/2020: This recipe also works when substituting buttermilk or acidulated milk (whole or 2% milk + a splash of white vinegar) for yogurt.