For the topping:
3/4 cup packed light brown sugar
1 ½ cups self-rising flour
6 tablespoons room temperature unsalted butter (3/4 stick), cut into small pieces

For the filling:
4 cups of peaches, peeled, sliced and each slice cut into 1-inch pieces
1 tablespoon freshly squeezed lemon juice
1 teaspoon cinnamon

For the topping:
Heat the oven to 425°F and arrange a rack in the middle.
Place all of the ingredients in a mixing bowl. With your fingertips, blend the butter pieces into the dry ingredients until large clumps form and the flour and butter are completely incorporated about 3 minutes.

For the filling:
Combine the peaches with lemon juice and cinnamon. Spread the peaches in a medium baking dish, greased with butter. Sprinkle the crumb topping over the peaches.
Bake until the topping is browned and crisp, about 20 to 25 minutes. Place the dish on a wire rack to cool for at least 30 minutes before serving.