Preparation

Make the streusel

In a medium bowl, whisk together the flours, brown sugar, and salt. In a medium microwave-safe bowl, combine the butter and almond butter. Microwave until melted, about 1 minute, stirring halfway through. Whisk until smooth and combined, then pour into the dry mixture. Stir just until large crumbs form.

Make the muffins

In a medium bowl, whisk together the flours, baking powder, lemon zest, salt, and nutmeg.

In a large bowl, beat the butter and granulated sugar using an electric mixer on medium-high until light and fluffy, about 3 minutes. Add the egg and vanilla. Beat until well combined. Reduce the speed to low. Add half the flour mixture, then half the milk. Repeat with remaining flour mixture and milk.

Measure 1/2 cup of the streusel crumbs and gently fold into the batter with the blueberries just until evenly distributed, being careful not to break up the streusel too much.

Using a cookie scoop or 1/4-cup measuring cup, scoop a scant 1/4 cup of the batter into each lined muffin cup. Top each with a generous sprinkle of streusel, pressing gently with fingers to adhere streusel to the top of the muffin batter.

Bake until lightly golden on top, about 25 to 28 minutes. Cool in muffing tin on a wire rack 10 minutes. Serve warm or at room temperature.