1. Preheat the oven to 375°F (190°C). Line a muffin tin with 10 large tulip paper liners* and set aside.

 

2. For the streusel add the flour, muscovado sugar, and vanilla sugar to a bowl and mix well. Add the butter in small pieces and rub everything between your fingers until streusel form. Place in the fridge until needed.

 

3. Melt the butter and let cool down a bit. Add to a large bowl and mix with the muscovado sugar, sour cream, vanilla extract, lemon zest, and egg until well combined. Mix the four with baking powder, baking soda, and salt – add to the bowl and mix until just combined. Add the blueberries and fold in. Divide the batter between the paper liners and sprinkle with the streusel. Bake for 25-30 minutes or until a wooden skewer inserted into the center of the muffins comes out clean. Take out of the oven, take the muffins out of the tin and place on a wire rack to cool down completely.