For the Blueberry Cornflake Muffins

• First, make the cornflake streusel. In a small bowl, combine the butter and brown sugar. Toss with your fingertips, rubbing the sugar into butter, until the mixture is combined and crumbly with lima bean- and pea-sized clumps. Add the cornflakes and toss to combine, lightly crushing the cornflakes into the clumps. Refrigerate while you make the muffin batter.
• Prep your oven and pan. Position a rack in the center of the oven and preheat the oven to 400°F. Line a muffin pan with 12 paper liners.
• Make the muffin batter. In a medium bowl, whisk together the flour, baking powder, and salt. In a small liquid measuring cup, whisk together the milk and the vanilla.
• In the bowl of a stand mixer fitted with the paddle attachment, combine the sugar and butter. Beat on medium-high until light, fluffy, and doubled in volume, 2 to 3 minutes, using a rubber spatula to scrape down the bottom and sides of the bowl as necessary. Reduce the mixer to low and add the eggs one at a time, adding the next egg only after the previous one is fully incorporated, scraping down the bottom and sides of the bowl after each addition.
• With the mixer on low, add the dry ingredients in two equal parts, adding the second half only when the first half has been just combined. Beat until just combined, then scrape down the bottom and sides of the bowl once more, then beat on low for an additional 30 seconds. Slowly pour in the milk and vanilla in a steady stream down the side of the bowl and beat until just combined, 30 to 45 seconds. Scrape down the bottom and sides of the bowl once more, then add the blueberries all at once. Beat on low until just combined.
• Use a 1-tablespoon cookie dough scoop to fill each lined cavity with 5 Tablespoons of batter. Sprinkle the top of each muffin, aiming for the batter and avoiding the pan, with 1 Tablespoon of the cornflake streusel.
• Bake the muffins. Bake for 22 to 24 minutes, or until the muffins are domed and golden brown around the edges. A skewer inserted into the center of a muffin should come out with few crumbs attached. Cool the muffins in their muffin tin on a wire rack for 15 minutes, then use an offset spatula to run underneath the edges of any large blueberry muffin tops to prevent them from sticking in the pan. Be careful to just run the offset spatula under the edges—you don't want to accidentally cut into the muffin bottom and decapitate the muffin from its top!
• Serve and store. Serve warm or at room temperature. The muffins can be wrapped individually in plastic wrap and stored at room temperature for up to 2 days.