Brush each slice of watermelon with olive oil on both sides. Then drizzle with lemon juice.
The air fryer basket can be lined with parchment if you like. Put the watermelon pieces in the basket and air fry at 400°F (200°C) for 5 minutes.
Then flip the watermelon to the other side and fry for another 2-3 minutes.
Transfer the watermelon to plates. Add crumbled feta cheese, mint leaves, and cinnamon. Drizzle with balsamic vinegar before serving.
Notes
Seedless watermelon works best for this recipe, but you can use melon with seeds. Just pick them out before cooking!
You can remove the rind if you like. Leaving it on reminds everyone that they are indeed eating watermelon, but leaving it off will give this recipe more of a "watermelon steak" feeling.
Look for a whole piece of feta, rather than pre-crumbled cheese. The flavor and texture is so much better.
This dish is perfect for summer, with sweet, savory, and fresh flavors. Serve it as a vegetarian meal or as a side dish with grilled meat.