1 small watermelon (about 6 lbs), cut into 1-inch thick rounds (lay melon on its side & cut through rind and flesh with a sharp knife)
1/2 cup small mint leaves, torn
2 ounces feta cheese, crumbled into large chunks
1 tbsp. olive oil
1 tbsp. balsamic vinegar
1/4 tsp. sea salt
1/4 tsp. black pepper
Heat a grill or grill pan over high heat until very hot. Two at a time, grill watermelon rounds, turning once, until charred (about 2-3 minutes per side). Transfer watermelon to a cutting board and remove rind; cut rounds into wedges.
Arrange watermelon on a serving platter; sprinkle with mint and feta. Drizzle with olive oil and vinegar, then sprinkle with salt and pepper.