To make the streusel:

1. Combine the flour, brown sugar, sugar, baking powder, and salt in a medium sized bowl. Stir in the butter until clumps form. Set aside while you make your muffins.

To make the muffins:

1. Preheat the oven to 400 degrees and move one rack to the upper third of the oven, leaving enough room for the muffin pan up top. Line a 12 compartment muffin tin with liners and set aside.
2. In a large bowl, stir the butter and sugar until well combined. Add the eggs, one at a time, stirring after each addition. Add the vanilla and lemon zest, stirring until combined.
3. In a separate, smaller bowl, combine the flour, baking powder, and salt. Add half of the dry ingredients to the butter and egg mixture, stirring until combined. Add the milk, stir, and then add the remaining dry ingredients. Stir to combine. Fold in the peaches, being careful to not overwork the batter.
4. Divide the muffin batter amongst the 12 muffin liners. Depending on your liners, you may have a hair too much batter. Just fill as much as you feel comfortable- they will be FULL. Don’t worry! Divide the streusel among the 12 muffins, sprinkling on top.
5. Put the muffin pan on the top rack and immediately decrease the heat to 375. Bake at this temperature for 10 minutes, then decrease the heat to 350 and bake for an additional 22-25 minutes, or until the muffins are set and a toothpick inserted comes out clean. The muffins should be starting to bronze around the edges. Allow to cool slightly before topping with the glaze.

To make the glaze:

1. Whisk together all three ingredients. Drizzle over top of slightly cooled muffins.