Cinnamon Quick Bread with Sour Cream

Instructions:

1. Preheat the oven to 350°F (175°C) and grease a 9x5 inch loaf pan, lining it with parchment paper.
2. In a medium bowl, whisk together the 250g flour, 150g granulated sugar, baking powder, baking soda, and salt.
3. In a large bowl, whisk the melted butter, eggs, sour cream, and vanilla extract until the mixture is smooth and pale.
4. Gently fold the dry ingredients into the wet ingredients using a spatula until no streaks of flour remain, taking care not to over-mix.
5. In a small ramekin, combine 65g brown sugar and 16g ground cinnamon for the swirl.
6. Pour half of the batter into the prepared loaf pan. Sprinkle half of the cinnamon-sugar mixture evenly over the batter.
7. Pour the remaining batter on top, then sprinkle the rest of the cinnamon sugar.
8. Use a butter knife to gently swirl the cinnamon mixture into the batter in a figure-eight motion.
9. Pinch the streusel topping ingredients (30g flour, 50g brown sugar, 28g cold butter) together and scatter them over the top.
10. Bake for 60 minutes or until a toothpick inserted into the center comes out clean.