Preheat oven to 350 degrees. In a large pot of boiling water, cook pasta according to package until al dente, about 12 minutes. Rinse penne under cold water and drain. Set aside. Heat 1 tbsp of oil in a skillet over medium. Add garlic and stir until fragrant. Add spnach and 2 cups of tomato. Cook for 4 minutes, until spinach wilts.
In a medium bowl, combine remaining 1 cup of tomato, herbs, and salt. Transfer the cooked tomato mixture to the bowl and stir well. Add pasta to tomato mixture and combine thoroughly. Stir in 1/2 cup of cheese.
Grease bottom of baking dish with remaining 1 tsp oil. Pour pasta into dish. Bake uncovered for 15 minutes, then remove from oven and sprinkle with remaining 1/4 cup cheese. Bake until cheese metls, about 4 more minutes. Let stand for 5 minutes before serving.