Trim off the ends of the Brussels sprouts and remove any brown outer leaves. Cut them in half from stem to end. If any are very large, cut them into quarters.

(Optional) Place the Brussels sprouts in a large bowl and cover with warm tap water. Let sit for 10 minutes.

Preheat the air fryer to 375 degrees.

Drain the Brussels sprouts and pat them dry with a towel. In a large mixing bowl, drizzle with oil and sprinkle with salt and black pepper. Toss to coat evenly.

Add the Brussels sprouts to the fryer basket. Cook for 5 minutes, then shake the basket to toss the Brussels sprouts.

Cook for an additional 5 minutes, then shake the basket again.

Add the garlic cloves and cook for 2 to 4 additional minutes, checking and shaking the basket often, until the Brussels sprouts are deeply crisp.

If adding toppings, transfer the Brussels sprouts to a serving bowl and stir in any desired toppings.