Slice tomatoes ¼-inch thick. Lightly salt them and let them sit for 15–20 minutes. Pat thoroughly dry with paper towels.
Heat oven to 375°F (190°C) and lightly grease a 9-inch pie dish.
Whisk together cottage cheese, mayonnaise, eggs, onion, garlic, Italian seasoning, salt, and pepper. Stir in ¾ cup of the shredded cheese.
Layer half the tomatoes in the dish. Add some basil and half the cottage cheese mixture. Repeat with the remaining tomatoes and cheese mixture.
Sprinkle the remaining ¼ cup cheese over the top and bake for 35–45 minutes, until the center is set and the top is golden and bubbling.
Rest for 10–15 minutes before slicing. Garnish with fresh basil and serve warm.