Prepare the crumb topping by mixing 1 cup of all-purpose flour, 6 1/2 tablespoons of melted butter, ¼ cup of sugar, ¼ cup of light brown sugar, and 1 1/4 teaspoons of ground cinnamon in a medium bowl until crumbly.

In a large mixing bowl, whisk together 2 large eggs and gradually add in 1 cup of granulated sugar until smooth and slightly fluffy.

Add 1 cup of sour cream and 1/2 cup of vegetable oil into the egg mixture and stir gently to combine.

In another bowl, whisk together 2 cups of all-purpose flour, 3 teaspoons of baking powder, and ½ teaspoon of salt until evenly mixed.

Gradually fold the dry ingredients into the wet mixture gently with a spatula until just combined.

If using fresh peaches, slice them; if using frozen, thaw them fully. Toss the peaches with 2 tablespoons of flour to prevent sinking in the batter.

Fold the prepared peaches into the batter gently.

Preheat the oven; grease a 9-inch round cake pan. Pour the batter into the pan and smooth the top.

Sprinkle the crumb topping evenly over the batter.

Bake in the preheated oven until golden brown and a toothpick inserted in the center comes out clean.

Allow to cool in the pan before transferring to a wire rack.

Mix together powdered sugar and a splash of milk for the glaze and drizzle over the cooled cake.