Preheat your oven to 400 degrees Fahrenheit and prepare a cupcake pan with paper liners.

For the crumb topping, whisk together flour, sugar, brown sugar, and cinnamon in a small bowl. Then add the melted butter and mix until it resembles crumbs. Pop this in the fridge for now.

In a separate large bowl, combine the flour, baking powder, and salt. Set this aside.

In another medium bowl, whisk together sugar and eggs until well combined and frothy. Add in the sour cream, vegetable oil, and vanilla extract.

Gently fold the wet ingredients into the dry ones until just combined.

Reserve 1 cup of peaches for topping, and dust the rest with 1 tablespoon of flour. Gently fold the peaches into the batter.

Spoon the batter into the muffin tins, filling each cup about 2/3 full.

Top with reserved peaches and crumble the crumb topping over the muffins.

Bake at 400 degrees Fahrenheit for 5 minutes, then reduce the temperature to 375 degrees Fahrenheit and bake for another 15 minutes.

Check doneness with a toothpick; it should come out clean.

Let cool in the pan for about 5 minutes before transferring to a wire rack.

For a glaze, mix powdered sugar, vanilla, and milk to desired consistency.