Preheat your oven to 425°F and prepare a standard muffin tin by lightly greasing it or lining it with paper muffin cups. This ensures easy removal of the muffins later on.
In a medium bowl, combine the zest of 2 lemons with 1/2 cup granulated sugar and 1/3 cup brown sugar. Use your fingertips to rub the zest into the sugars until they are moist and aromatic. This step releases the oils from the zest, infusing the sugars with a delightful lemon flavor.
In a large mixing bowl or the bowl of a stand mixer fitted with a paddle attachment, cream together 1/4 cup unsalted butter, 1/4 cup vegetable oil, and the lemon-sugar mixture until it’s smooth and fluffy. Add in 2 large eggs and 1 teaspoon pure vanilla extract, beating until everything is well combined and creamy.
In another bowl, whisk together 2 2/3 cups all-purpose flour, 1 1/2 teaspoons baking powder, 1/4 teaspoon baking soda, and 3/4 teaspoon salt. Gradually stir this dry mixture into the wet mixture, alternating with 1 cup milk. Start and end with the flour mixture to ensure even distribution. Mix until just combined, being careful not to overmix.
Gently fold in 1 1/3 cup fresh blueberries, ensuring they’re evenly distributed throughout the batter without breaking them apart. This will give you pockets of juicy blueberries in your muffins.
Using a spoon or an ice cream scoop, fill the prepared muffin cups nearly to the top with the batter. This will help create those delicious muffin tops that we all love!
Bake the muffins in the preheated oven for about 15 to 17 minutes. Keep an eye on them; they should turn a pale golden brown, and a toothpick inserted into the middle of one of the center muffins should come out clean when done.
While the muffins bake, prepare the glaze. In a medium bowl, combine 3 tablespoons melted unsalted butter, 1 cup confectioners’ sugar, 1/2 teaspoon pure vanilla extract, 1 tablespoon freshly squeezed lemon juice, and 1 tablespoon warm water. Whisk until smooth; it should be a pourable consistency.
Once the muffins have cooled slightly, dip the tops into the glaze, allowing the excess to drip off. You can let the glaze set or go for a double dip for an extra sweet layer!
Serve the muffins warm or allow them to cool on a wire rack. They can be stored in an airtight container at room temperature for about a day, but I doubt they’ll last that long with how delicious they are!