- Combine flour, sugar, cinnamon, and salt in a large bowl.
- Use a pastry cutter or a fork to work in Butter until the mixture is pea-sized.
- Mix in the apples. Keep in the refrigerator until ready for use.
- Preheat the oven to 350°F. Butter, flour, and parchment paper are all you need to make two 9x5" loaf pans. Set aside.
- Mix the dry ingredients in a large bowl: flour, baking powder and baking soda. Set aside.
- Use the paddle attachment to beat Butter and sugar in a bowl with a stand mixer. Blend until light and fluffy, approximately 4 minutes. Scrape the bowl's sides and bottom.
- Mix eggs one at a while, beating well between each addition.
- Mix in vanilla, and mix well.
- Mix the dry ingredients in a bowl. Turn the mixer to low. Next, add half the sour cream.
- Continue to add another third of the dry ingredients. Continue to add the remaining sour cream. Mix everything until well combined
- Add apple chunks.
- Divide the batter equally between the prepared pans. Sprinkle the crumble mixture on top of each pan.
- Bake for approximately 50 minutes or until a toothpick inserted into the center comes clean.
- Allow cakes to cool down for around 15 minutes, then take them out of the pans. To cool completely, place on a rack.