1. Preheat oven to 350°F (175°C) and line an 8×8-inch pan with parchment paper.

2. In a bowl whisk flour, baking powder, salt, and 1 teaspoon cinnamon.

3. In another bowl cream butter and granulated sugar until light, then beat in eggs one at a time and vanilla.

4. Fold in sourdough discard until combined.

5. Alternate adding dry ingredients and milk to the wet mixture, beginning and ending with dry ingredients.

6. In a separate bowl combine brown sugar, flour, melted butter, and 1 teaspoon cinnamon to form crumb topping.

7. Pour half the batter into the pan, sprinkle half the crumble, add remaining batter, then top with remaining crumble.

8. Bake for 35 minutes or until a toothpick comes out with moist crumbs.

9. Cool in pan for 15 minutes then transfer to a wire rack.

10. Slice and serve warm or at room temperature.