Preheat the oven to 350 degrees and line a small baking sheet with parchment paper.

In a mixing bowl, cream the softened butter with the granulated sugar until light. Add the eggs one at a time and mix until combined.

Stir in the milk. In a separate bowl, whisk together 1 1/2 cups flour and baking powder, then fold the dry mixture into the wet ingredients until just smooth.

Spread the batter evenly onto the prepared baking sheet. Arrange the apple slices over the top in a single layer.

To make the crumb, combine the remaining 1/2 cup flour, brown sugar, and cinnamon in a bowl. Cut in the cold butter until the mixture forms coarse crumbs, then sprinkle evenly over the apples.

Bake for 30 to 35 minutes until the crumb turns golden and a toothpick inserted in the center comes out clean.

Remove from the oven and let cool slightly before drizzling with the caramel sauce.