• Preheat the oven to 350 degrees F. Spray a 9x13 baking dish with nonstick baking spray.
• In a bowl, whisk together the melted butter and brown sugar. Whisk in the apple butter. Whisk in the eggs one at a time, then the vanilla extract.
• In a smaller bowl, whisk together the flour, baking powder, soda, cinnamon and salt. Stir the dry ingredients into the wet ingredients, stirring until just combined.
• Grate one of the honeycrisp apples. Stir it into the batter. Pour the batter into the baking dish.
• Thinly slice the remaining honeycrisp apple and remove the seeds. Place it on top of the batter.
• Bake the cake for 40 to 45 minutes, or until a tester inserted in the center comes out clean.
• Remove the cake and let it cool slightly. Sprinkle it with powdered sugar. And/or drizzle with the brown butter icing.

brown butter icing

• Place the butter in a skillet over medium heat. Cook and let the mixture bubble, stirring occasionally, until brown bits begin to appear on the bottom. Once the brown bits appear, turn the heat off and continue to stir for about 30 seconds. Let the butter cool slightly.
• Whisk in the powdered sugar and vanilla extract. You want a smooth glaze, so add in 1 tablespoon of milk at a time, whisking until smooth and drizzle-able. Drizzle or spread on the cake!