Marinate sliced tomatoes with balsamic vinegar for 4-6 hours. Bake at 350 for about 7 minutes or a little tender.
Meanwhile, sauté spinach and garlic with a dash of salt and lemon juice. Put spinach on top of tomatoes and sprinkle with cheese of your choice (I chose Italian blend) and broil til cheese is golden! Ta da. Delish and muffin top friendly! Enjoy!