• Preheat oven to 375℉ (190℃). If using a convection fan oven lower the temp by 25℉ (20℃). Prepare a 6-capacity large muffin tray with non-stick baking spray or good ole butter and flour. If using paper liners, there's no need to prep the pan.

Crumble

• Melt the butter and let it cool until it has slightly thickened. Stir together all the ingredients in a medium bowl using a fork. Leave the crumble a little chunky. Set aside.
  40 grams all purpose flour, 50 grams old fashioned oats, 50 grams granulated sugar, 57 grams unsalted butter , 1 tsp ground cinnamon, 1 Tbsp brewed coffee

Muffins

• Whisk together flour, baking powder and salt in a small bowl.
  250 grams all purpose flour, 15 grams baking powder, 1/2 tsp fine sea salt
• In a large mixing bowl with whisk together the sugar, eggs, yogurt, oil, vanilla, and coffee.
  100 grams eggs, 150 grams granulated sugar, 4 tablespoons brewed coffee, 240 grams plain Greek yogurt, 60 grams sunflower oil, 2 tsp vanilla extract or vanilla bean paste
• Slowly stir in half of the flour mixture at a time to make a thick batter.
• Toss juicy blueberries in 2 teaspoons of flour for a light dusting. 
  270 grams fresh blueberries, 2 tsp all purpose flour
• Add the blueberries to the muffin batter. Gently fold them in with a rubber spatula until evenly distributed.
• Divide the batter evenly amongst the six cavities in the muffin pan. Fill about 3/4 to 4/5 of the way full. To prevent berries from all sinking to the bottom, spoon a little of the plain batter into the bottom of each cavity, then continue to fill with batter mixed with the blueberries.
• Top the batter with a few extra small fresh blueberries.
• To finish, add the crumble to the batter. Sprinkle it in chunks to loosely cover each muffin. Gently tap the topping with your fingertips to stick to the batter.
• Transfer the pan to the middle oven rack and bake for 28-30 minutes or until a toothpick inserted into the middle comes out clean. You may have a little jammy blueberry on the toothpick, but if the muffin top gently springs back when pressed with your fingertip, they're ready!
• Place the pan on a wire rack to cool for 15 minutes. Then carefully remove the muffins and place them directly onto the rack to completely cool. Since they have large tops, I invert the pan a little and slowly twist the muffins out, if not using paper liners.