Set the oven to 350°F (175°C). Lightly grease a 9×13-inch baking pan or line it with parchment paper. If you’re not using parchment, dust the pan with a little flour to help prevent sticking.

In a large bowl, beat the softened butter with both the granulated and brown sugar until the mixture is light and fluffy. This usually takes about 3 to 4 minutes using an electric mixer on medium speed.

Add the eggs one at a time, beating well after each addition. Once the eggs are fully mixed in, stir in the apple butter until smooth. Be sure to scrape the sides of the bowl as you go to keep everything evenly mixed.

In another bowl, whisk together the flour, baking powder, salt, and apple pie spice. This helps ensure the leavening and spices are evenly spread throughout the batter.

Gradually add the dry ingredients to the wet mixture. Mix on low speed until just combined. Be careful not to overmix, as that can make the cake dense.

Pour the batter into the prepared pan and spread it out evenly. Bake for 35 to 40 minutes, or until a toothpick inserted in the center comes out clean or with a few moist crumbs. Let the cake cool in the pan for about 10 minutes, then transfer it to a wire rack to cool completely.

In a clean bowl, beat the softened cream cheese and butter until smooth. Gradually add the powdered sugar and beat until well combined. Add milk or cream a tablespoon at a time to adjust the consistency, then stir in the vanilla. Once the cake is completely cool, spread the frosting over the top using a spatula.

Cut into slices and serve. If you’ve frosted the cake, it’s best stored in the fridge, where it will keep for up to 5 days. If left unfrosted, it can sit at room temperature for up to 2 days, covered.