Step 1

Pre-heat the oven to Line a muffin pan with paper cups.

Step 2

Brown the butter. (To brown your butter, melt it in a saucepan over medium heat. After it gets frothy and then sounds like your morning bowl of Rice Krispies for a bit, the butter will settle down and begin to brown. You’re looking for a medium golden brown color and a little bit of a nutty smell) Pour the butter immediately into a small bowl so it doesn’t continue to brown and burn.

Step 3

In a medium bowl whisk together the milk, egg, yolk, and vanilla. VERY slowly, drizzle the browned butter in a little at a time, whisking well while you add. This tempers the egg and milk so it doesn't scramble in the bowl.

Step 4

In a large bowl whisk together the flour, sugar, baking powder, and salt. Dump the milk/egg mixture into the flour mixture and mix it all together. The batter will be THICK.

Step 5

Stir in the lemon zest and blueberries until the batter has just combined, and then divide the batter evenly between the 12 lined muffin cups.

Step 6

Using your fingers, crumble the 3 tablespoons of butter with the flour and sugar to make the streusel topping. You are looking for coarse crumbles. the mixture over the muffin batter.

Step 7

Bake the muffins for 18 to 20 minutes until the crumbly topping is golden and a skewer inserted into the center of the muffins comes out clean.