01 - Preheat oven to 375°F. Line a 12-cup muffin tin with paper liners or lightly grease with butter.
02 - In a medium bowl, whisk together flour, baking powder, baking soda, and salt until well combined.
03 - In a large bowl, whisk melted butter and sugar until combined. Add eggs, yogurt, milk, lemon zest, and lemon juice; whisk until smooth and fully incorporated.
04 - Gently fold dry ingredients into wet mixture until just combined. Do not overmix—small lumps are acceptable.
05 - Carefully fold in blueberries until evenly distributed throughout the batter.
06 - Divide batter evenly among the muffin cups, filling each about 3/4 full.
07 - In a small bowl, combine flour, sugar, and salt. Add cold cubed butter and use your fingers or a pastry cutter to work butter into the mixture until coarse crumbs form.
08 - Sprinkle streusel evenly over each muffin. Bake for 20-22 minutes, or until a toothpick inserted in the center comes out clean.
09 - Allow muffins to cool in the pan for 5 minutes, then transfer to a wire rack to cool completely before serving.