Preheat your oven to 375°F (190°C).
Slice the tops off the bell peppers and remove seeds.
In a bowl, mix drained tuna, red onion, cherry tomatoes, feta cheese, olives, olive oil, parsley, basil, salt, and pepper until combined.
Stuff each bell pepper generously with the tuna mixture and place them upright in a baking dish.
Bake for 25-30 minutes or until the peppers are tender and slightly charred at the edges.
Drizzle with fresh lemon juice before serving.
