01 -
In a small bowl, mix together the melted butter, sugar, and flour using a fork until it forms a crumbly mixture. Put it aside for now.
02 -
Preheat the oven to 350°F (176°C). Use muffin liners for your 12-cup muffin pan or grease the pan to keep things from sticking.
03 -
In a large bowl, stir together the flour, sugar, baking powder, baking soda, corn starch, salt, and lemon zest. Toss the blueberries in the mixture to coat them so they won’t sink to the bottom of your muffins.
04 -
Whisk all the wet ingredients in a medium bowl until smooth. Pour the wet mixture into the dry mixture and gently stir until just combined. If it’s too thick, add a little splash of milk or water (around 1–2 tablespoons).
05 -
Fill the muffin pan cups evenly with the batter. Sprinkle the crumb topping on top of each, lightly pressing the crumbs into the batter so they’ll stay in place after baking.
06 -
Bake the muffins for about 30–35 minutes. To check if they’re ready, stick a toothpick in the center and see if it comes out clean. Cool them for 10 minutes in the pan, then transfer them to a rack to finish cooling off.