Step 1

Toss together Brussels sprouts and olive oil in a large bowl until thoroughly coated.

Step 2

Preheat air fryer to 350°F for 6 minutes. Lightly coat basket with cooking spray. Add Brussels sprouts to basket, and cook until golden brown and crispy, 20 to 25 minutes, stirring halfway through cooking.

Step 3

Meanwhile, trim both ends off lemon. Stand lemon on 1 end. Using a sharp knife, carefully cut peel and white pith away from lemon flesh, starting at the top end and moving down toward the bottom end; discard peel. Slice along each section, removing lemon segment from membrane; reserve lemon membrane and segments separately. Cut reserved lemon segments into small cubes to equal 1 1/2 tablespoons; set aside. Squeeze juice from reserved lemon membrane to equal 1 teaspoon.

Step 4

Transfer Brussels sprouts to a medium bowl, and toss with butter, thyme, lemon juice, and cubed lemon segments. Transfer Brussels sprout mixture to a platter, and sprinkle evenly with grated cheese; serve immediately.