Cream together sugar, butter, and egg until light and fluffy.

Stir in milk and lemon extract until well combined.

In a separate bowl, whisk together flour, baking powder, and salt.

Gradually blend the dry ingredients into the wet ingredients until just combined. Do not overmix.

Grease a 2-quart baking pan thoroughly.

Spread the batter evenly into the bottom of the prepared pan.

Pare and slice apples thinly.

Arrange the apple slices evenly on top of the batter.

In a small bowl, cut butter into the sugar, cinnamon, nutmeg, and flour until it forms a crumbly mixture.

Sprinkle the crumbly mixture evenly over the apple slices.

Bake in a preheated oven at 350°F (175°C) for 40-45 minutes, or until a wooden toothpick inserted into the center comes out clean.

Let the cake cool slightly before serving.