01 -
Whisk together the all-purpose flour, baking powder, baking soda, salt, ground cinnamon, and ground nutmeg in a medium bowl until evenly combined.
02 -
Beat the softened unsalted butter with granulated sugar on medium-high speed for 2 to 3 minutes until pale and fluffy.
03 -
Add eggs one at a time, beating well after each addition, then stir in the vanilla extract, scraping down the bowl as needed.
04 -
Mix in the sour cream until the batter is smooth and well blended.
05 -
Gently fold the dry ingredient mixture into the wet ingredients until no dry spots remain, taking care not to overmix.
06 -
In a small bowl, toss peeled and chopped Honeycrisp apples with brown sugar and ground cinnamon until evenly coated.
07 -
Pour half of the batter into a greased loaf pan, evenly distribute half of the apple mixture over the batter, then top with remaining batter and apples. Use a butter knife to gently swirl for a marbled effect.
08 -
Bake in a preheated oven at 350°F (175°C) for 50 to 60 minutes, or until a toothpick inserted in the center comes out with a few moist crumbs. Cool in the pan for 10 minutes, then transfer to a wire rack to cool completely.