For the crumble:
1/3 cup (40 grams) light brown sugar
1/3 cup (35 grams) all-purpose flour
1/4 cup (25 grams) rolled oats
1/4 teaspoon ground cinnamon
1/4 teaspoon kosher salt
4 tablespoons (1/2 stick) cold unsalted butter, cut into small cubes
1/3 cup chopped pecans or walnuts (optional)
For the muffins:
1/2 cup (1 stick) unsalted butter, room temperature, plus more for the pans
3/4 cup (90 grams) all-purpose flour
3/4 cup (90 grams) whole-wheat pastry flour
2 teaspoons baking powder
1 teaspoon ground cinnamon
1/2 teaspoon ground ginger
1/2 teaspoon ground cardamom
3/4 teaspoon kosher salt
1/2 cup (100 grams) granulated sugar
3/4 cup plain full-fat yogurt or sour cream
1 teaspoon vanilla extract
2 large eggs
For the glaze:
1/4 cup powdered sugar
1 1/2 teaspoons milk
Prepare crumble topping: In a small mixing bowl, whisk together the brown sugar, flour, oats, cinnamon, and salt. With a pastry blender (or using your fingertips and a quick rubbing back-and-forth motion), cut in the butter until the mixture resembles large peas. With a fork, fold in chopped nuts, if using. Refrigerate until ready to use.
Prepare muffins: Preheat oven to 350°F. Butter 10 wells in a standard 12-well muffin tin (or use paper muffin liners). In a medium bowl, whisk together flours, baking powder, cinnamon, ginger, cardamom and salt; set aside.
Using a stand mixer fitted with the paddle attachment (or hand beaters on medium speed), beat together the butter and sugar until light in color and fluffy, about 3 to 5 minutes. Scrape down the sides as needed. Add the yogurt and vanilla and continue to beat until incorporated. Beat in eggs, one at a time, until combined. Set the mixer on low and stir in the flour mixture – be careful not to overmix.
Divide the batter evenly among prepared muffin cups. Top with the crumble topping. Bake for 25 to 30 minutes or until a toothpick inserted in center of a muffin comes out clean. Cool in pan 10 minutes, then transfer to a wire rack to cool completely.
Prepare glaze: Whisk together the sugar and milk. If too thin, add a teaspoon more sugar; if too thick, add 1/2 teaspoon more milk. Continue to add until the consistency is like a thick, pourable glaze.
Once the muffins are completely cool, drizzle glaze over the tops.
Recipe Notes
- You want to be very, very generous in your application of crumble topping: the muffin tops spread as they bake and what once looked like a grea