• Preheat the oven to 375℉/190℃. Line the muffin tin with liners and set aside.

Make the streusel

• In a bowl add the butter, flour, and sugar. Mix together with your hands or a fork until a crumbly streusel forms. Set in the fridge to chill.
  3/4 cups all-purpose flour, 5 tbsp unsalted butter, 1/3 cup white sugar

For the muffins

• Into a bowl add the flour, baking soda, baking powder, cornstarch, and cinnamon. Stir to combine and set aside.
  2 1/2 cups all-purpose flour, 2 tsp baking powder, 1 tsp baking soda, 1 1/2 tsp cornstarch, 1/4 tsp cinnamon
• Into a large bowl add the white sugar, vanilla, yogurt, melted butter, oil, eggs, and lemon zest. Whisk together.
  1/4 cup unsalted butter, 1/3 cup oil, 2 large eggs, 1 cup yogurt, 1/2 tsp lemon zest, 3/4 cups white sugar, 2 tsp vanilla
• Combine the dry and wet ingredients with a spatula until a soft muffin batter forms. Do not over-mix!
• Into the bowl with the mixed berries, add 1 tsp of flour and evenly coat the berries in it. This will prevent them from sinking as they bake.
  2 cups mixed fruits*
• Add them into the muffin batter and stir to combine. Don't over-mix!
• Scoop the batter into the liners, filling them to the top. Sprinkle a handful of streusel on top of each one.
• Bake for 20-25 minutes, or until a toothpick inserted comes out clean.
• These muffins are such a treat! Enjoy!