Preheat your oven to 350°F (175°C) and grease a 9-inch round cake pan with butter or non-stick spray. Line the bottom with parchment paper.

In a medium bowl, whisk together 1 ½ cups of all-purpose flour, 1 teaspoon of baking powder, and ¼ teaspoon of salt until well combined.

In a large bowl, whisk 3 large eggs with 1 cup of granulated sugar until pale and frothy, then add ½ cup of melted butter, ½ cup of whole milk, and 1 teaspoon of vanilla extract. Stir until smooth.

Fold the dry ingredient mix into the wet mixture until just incorporated, being careful not to overmix.

Fold in the peeled and sliced apples until they are evenly distributed in the batter.

Pour the thick batter into the prepared cake pan and smooth the top.

Bake in the oven for 40-45 minutes, checking for doneness with a toothpick. It should come out clean when the cake is done.

Allow the cake to cool in the pan for about 10 minutes before transferring it to a wire rack. Dust with powdered sugar if desired before serving.