Blueberry-Buttermilk Muffins with Lemon Crunch Topping

Method

1. Position an oven rack in the center of the oven and preheat the oven to 190ºC. Line the muffin pan with baking cup liners. Set aside.
2. First make the topping. Place the brown sugar in the bowl of your 4.8L Artisan Stand Mixer fitted with the flat beater. Attach the Sifter + Scale Attachment to your mixer. Close the ingredient valve. Weigh the flour, sugar, baking powder, and salt in the ingredient hopper, taring the scale between ingredients. Turn the mixer to medium-low speed, open the ingredient valve, and sift the flour mixture into the mixing bowl. Mix until the dry ingredients are evenly combined, about 1 minute.
3. In a medium bowl, stir together the melted butter, lemon zest, and vanilla.
4. Turn the mixer to medium-low, slowly pour the butter into the dry ingredients, and mix just until combined. Turn the mixer off. Use a rubber spatula to scrape down the sides of the mixing bowl, and transfer the topping to a medium bowl. (The topping is very dense and buttery. Let it sit a bit before crumbling with your fingers.)
5. To make the muffins, wipe out the mixer bowl and the flat beater. Close the ingredient valve, and weigh the flour, sugar, baking powder, and salt in the ingredient hopper. Turn the mixer to medium-low speed, open the ingredient valve, and sift the flour mixture into the mixing bowl. Mix until the dry ingredients are evenly combined, about 1 minute.
6. In a medium bowl, whisk together the buttermilk, oil, eggs, lemon zest, and vanilla.
7. With the mixer on medium-low speed, slowly pour the buttermilk mixture into the flour mixture. Be careful not to overmix the batter. Turn the mixer off, remove the mixer bowl, and use a rubber spatula to blend in any flour remaining on the sides of the bowl. Fold in the blueberries.
8. Using a 1/3 cup, portion the batter into each of the 12 prepared muffin cups. Sprinkle the lemon crunch topping over each muffin, dividing it evenly. Baked the muffins until rounded on top, the topping is golden, and a toothpick inserted into the center comes out clean, 30 to 32 minutes. Cool the muffins in the pan set on a wire rack for 5 minutes. Lift out the muffins and set them on a wire rack to cool for at least 10 minutes before serving. The muffins are best when served on the day they are baked. The muffins will keep for 2 days in a covered container.