This classic recipe for zucchini muffins is the perfect way to take advantage of summer’s bounty of squash. The cinnamon-streusel topping gives each muffin an extra bite of sweetness and a delicate crunch.
Muffins: In a large bowl, whisk together the flour, baking powder, baking soda, cinnamon, nutmeg and salt. In the bowl of an electric mixer, combine the eggs, sugars, oil, and vanilla on low speed for about 1 minute, or until well incorporated. Add the dry ingredients to the egg mixture and mix on low speed until just combined. Fold in the grated zucchini. Divide the batter between the muffin papers and set aside while you make the streusel.
Streusel: In a medium bowl, whisk together the flour, sugar, cinnamon, and salt. Cut the cold butter into the mixture until crumbly using a pastry blender or a fork.
Sprinkle about 2 teaspoons of the mixture evenly over each muffin. Avoid piling the streusel in the middles of the muffins or they will sink in the middle during baking. Bake for 20-25 minutes, or until a toothpick tester comes out clean. Transfer to a wire rack to cool slightly.
Glaze: Whisk together the confectioners’ sugar and milk in a small bowl. Drizzle over muffins or transfer to a piping bag and pipe zigzag lines of glaze on top. Serve warm. Store in an airtight container or covered well with plastic wrap.