Ingredients:

  • 125g all-purpose flour
  • 150g brown sugar, packed
  • 2 tsp ground cinnamon
  • 115g unsalted butter, melted
  • 0.25 tsp salt
  • 450g Granny Smith apples, peeled and diced
  • 25g granulated sugar
  • 1 tsp ground cinnamon
  • 250g all-purpose flour
  • 2 tsp baking powder
  • 0.5 tsp baking soda
  • 0.5 tsp salt
  • 115g unsalted butter, softened
  • 200g granulated sugar
  • 2 large eggs, room temperature
  • 2 tsp vanilla extract
  • 240g sour cream

Instructions:

  1. Preheat your oven to 350°F (175°C). Grease a 9x9 inch square baking pan and line it with parchment paper.
  2. In a medium bowl, whisk together 125g flour, 150g brown sugar, 2 tsp cinnamon, and 0.25 tsp salt. Stir in 115g melted butter until moist clumps form to create the streusel.
  3. Toss the diced apples with 25g granulated sugar and 1 tsp cinnamon in a separate bowl.
  4. In a large bowl, cream 115g softened butter and 200g granulated sugar until light and fluffy. Beat in eggs one at a time, then add vanilla extract.
  5. Sift together 250g flour, baking powder, baking soda, and salt. Alternately add the dry ingredients and the sour cream to the wet mixture, beginning and ending with the dry ingredients.
  6. Spread half of the cake batter into the pan. Top with half of the spiced apples. Spread the remaining batter over the apples, followed by the rest of the apples.
  7. Distribute the cinnamon streusel evenly over the top.
  8. Bake for 45–55 minutes until a toothpick inserted in the center comes out clean.
  9. Cool in the pan for 20 minutes before slicing.