Preheat oven to 400 degrees F. Using a knife or spoon (I actually used a grapefruit knife), gently scoop out the seeds and flesh of he tomato. Discard or eat if desired. Drizzle 2 tablespoons of olive oil over tomatoes, then 1/4 teaspoon each of salt and pepper. Roast for 12-15 minutes, just until tomatoes are juicy and soft. Don’t over-roast here because the “cups” will collapse and be unstuffable.
While tomatoes are roasting, add tuna, white beans and avocado to a large bowl. Mash with a fork until your desired consistency is reached, then add in remaining olive oil, salt and pepper, along with basil. Mash and mix well.
Remove tomatoes and gently spoon a teaspoon or 2 of tuna mixture into the tomato cups. Cover with a sprinkling of cheese and panko, then bake for another 5-8 minutes until cheese is melted and tuna is warm. Serve!