Steps
1. Heat the olive oil in a skillet over medium heat.
2. Add the sliced onions and cook, stirring occasionally, until they are soft and caramelized (about 10-15 minutes).
3. While the onions are cooking, cube the watermelon and crumble the feta cheese.
4. In a bowl, combine the watermelon and feta cheese.
5. Once the onions are caramelized, add them to the bowl with the watermelon and cheese.
6. Season the salad with salt and pepper to taste.
7. Toss gently to mix all the ingredients together.
8. Garnish with fresh mint leaves before serving.