Summer yields an abundance of zucchini from home gardens and grocers alike. With such an ample supply of this low-calorie summer squash, you may be looking for a simple, satisfying way to prepare a dish that uses zucchini as one of its main ingredients. Bisquick offers many easy zucchini recipes to choose from, including zucchini appetizers and zucchini pie. None satisfies quite as well as Bisquick's zucchini casserole called "Easy Garden Bake."

The recipe calls for 1 cup sliced zucchini, 1 large chopped tomato, 1 medium onion chopped, 1/3 cup grated Parmesan cheese, 1/2 cup of Bisquick, 1 cup of milk, 2 eggs, and salt and pepper to taste. For a lower-fat option, use Bisquick Heart Smart mix and nonfat milk and replace the eggs with 1/2 cup of fat-free egg product. Any type of low-fat cheese may also be substituted for the Parmesan.

After preheating your oven to 400 degrees, coat an 8-by-8-inch baking pan with nonstick cooking spray. Layer the zucchini slices, tomatoes, onions and cheese in the pan. In a separate bowl, mix all the remaining ingredients together and pour them over the vegetables. Bake for 35 minutes and cool for an extra five. Double or triple the recipe if you need to feed a larger crowd, as this recipe serves only four. If you choose to double the recipe, use a 9-by-13-inch baking pan. If you have leftovers, freeze the casserole for another meal.

Zucchini is a low-calorie food, with only 16 calories per one-cup serving. With the low-fat adaptations, the casserole contains 150 calories, 1.5 g saturated fat and zero trans fats per serving. This meal provides you with a solid 11 g of protein but only 1 g of fiber, so you may need a salad and a slice of whole-wheat bread to complete your balanced meal. One serving of the casserole also provides you with 25 percent of your daily recommended intake of calcium, according to Oregon State University's Micronutrient Information Center. Calcium is an essential nutrient for maintaining skeletal health.

The majority of zucchini's nutrients are located in the skin, so to retain maximum nutritional benefits never peel zucchini or other types of summer squash. If you are out of fresh tomatoes, it's OK to substitute canned. Try diced tomatoes with green chilies for extra flavor. Experiment with herbs to complement the taste of the fresh vegetables without adding any calories or fat to the recipe. If your garden is overflowing with vegetables, slice them up and add them in for an endless variety of casseroles.