In a large heavy bottomed saucepan with a tight fitting lid saute garlic with a dash of salt and pepper in the butter until fragrant.
Add the rice, spinach, water, 1/2 teaspoon coarse salt and a couple dashes of black pepper. Bring to boil then reduce heat to low and cover. Cook 20 - 25 minutes.
Fluff up the rice with a fork then add the half & half, tomatoes and Parmesan. Mix well. Season to taste with salt and pepper. If the mixture seems exceptionally thick you can stir in additional half & half.
Preheat oven to 400 degrees F. Slice the zucchini evenly in half lengthwise and scoop out the seeds to form a boat.
Fill with the rice, heaping over the top. Place in a large roasting pan or on a baking sheet. Bake 20 - 25 minutes until the zucchini is fork tender.
Sprinkle the top with additional Parmesan to serve.