Prep your air fryer and liners. Preheat the air fryer to 320°F (160°C) for 3–5 minutes.

Line silicone muffin cups or air fryer-safe ramekins with paper liners, or lightly grease them. Make sure they fit in your basket with space around each cup for airflow.

Mix dry ingredients. In a large bowl, whisk together 1 3/4 cups flour, sugar, baking powder, and salt until well combined. This prevents clumps and distributes the leavening evenly.

Whisk wet ingredients. In a separate bowl or large measuring cup, whisk melted butter, oil, milk, eggs, vanilla, and lemon zest until smooth.

The mixture should look uniform with no streaks of egg.

Combine wet and dry. Pour the wet mixture into the dry ingredients. Gently fold with a spatula until just combined. The batter should be thick and a bit lumpy—do not overmix.

Toss the blueberries. In a small bowl, toss the blueberries with the remaining 1 tablespoon flour.

This helps keep them from sinking. If using frozen berries, do not thaw; toss straight from the freezer.

Fold in the berries. Gently fold the floured blueberries into the batter. Try not to crush them to keep the batter from turning purple.

Fill the cups. Divide the batter evenly among 8–10 muffin cups, filling each about 3/4 full.

Sprinkle the tops with coarse sugar if you like a light crunch.

Air fry in batches. Place 4–6 filled cups in the air fryer basket, leaving space between them. Air fry at 320°F (160°C) for 12–16 minutes, until the tops are golden and a toothpick comes out with just a few moist crumbs.

Cool briefly. Let muffins cool in the cups for 5 minutes, then transfer to a rack to finish cooling. Repeat with the remaining batter.

Serve. Enjoy warm or at room temperature.

For extra flavor, add a little butter or a drizzle of honey.