1. Preheat the Oven: Start by preheating your oven to 350°F (175°C). Grease and flour a 9×13 inch baking pan.
2. Mix Dry Ingredients: In a medium bowl, whisk together the flour, baking powder, cinnamon, and salt.
3. Cream Butter and Sugar: In a large bowl, beat the butter and sugar together until light and fluffy. Add the eggs, one at a time, beating well after each addition. Stir in the vanilla extract.
4. Combine Mixtures: Alternately add the dry ingredients and milk to the creamed mixture, starting and ending with the dry ingredients. Stir until just combined.
5. Fold in Apples: Gently fold the sliced apples into the batter.
6. Bake the Cake: Pour the batter into the prepared baking pan, smoothing the top with a spatula. Bake for 40-45 minutes, or until a toothpick inserted into the center comes out clean.
7. Cool and Serve: Allow the cake to cool in the pan for 10 minutes, then transfer to a wire rack to cool completely. Serve as is or with your choice of toppings.

Notes

• Choosing Apples: For the best results, use a mix of sweet and tart apples like Granny Smith and Honeycrisp.
• Storage: Store leftover cake in an airtight container at room temperature for up to 3 days or refrigerate for longer shelf life.
• Serving Suggestion: For an extra treat, serve warm with a scoop of vanilla ice cream or a drizzle of caramel sauce.