Preheat the oven to 350°F (175°C) and lightly grease a 9x9-inch baking dish.
Cream the butter and sugar in a medium bowl using an electric mixer until light and fluffy.
Add the egg and vanilla to the butter mixture, and continue beating for 2-3 minutes until fully combined.
In a separate bowl, sift together the flour, salt, baking powder, baking soda, cinnamon, nutmeg, and cloves.
Gradually mix the dry ingredients into the wet ingredients on low speed until just combined.
Fold in the diced apples gently with a spatula.
Pour the batter into the prepared baking dish, spreading it evenly.
Bake for 50-55 minutes, or until a toothpick inserted in the center comes out clean.
Let cool for 10 minutes before slicing and serving.