Zucchini Feta Casserole

This is by far one of my favorite summertime dishes. It's fresh, flavorful and filling! I always end up with way too many zucchinis from my garden, so this is a great recipe to make because it uses a whole zucchini. My inspiration was originally from a Cooking Light recipe, however I have altered it to my tastes quite a bit over the years, so I don't think it's much like the original! The reason I like this meal so much is because you can adapt it to suit your mood and tastes. Sometimes I add tomatoes, use different cheeses, or add in chopped chicken breast. I was also thinking that artichokes would be great in this, although I haven't tried that yet. In addition, it's a really quite a healthy recipe! Overall, this meal is the perfect summertime dinner.
Ingredients
Adapted from Cooking Light

1 14.5 oz. box Penne Pasta
1 medium zucchini, thinly sliced
1 onion, chopped
3-4 cloves garlic, minced
2 boneless skinless chicken breasts, chopped and cooked (optional)
2 medium tomatoes, chopped (optional)
Extra Virgin Olive Oil
kosher salt
freshly ground black pepper
2 teaspoons all purpose flour
1/2 cup low sodium chicken stock
1/2 cup (2 oz.) crumbled feta cheese
1/2 cup (2 oz.) shredded part skim mozzarella cheese

Directions
Preheat oven to 400 degrees. Cook pasta in boiling salted water for about 10 minutes, or until al dente. Drain and set aside.

In a large saute pan over medium-high heat, add about 1-2 tablespoons olive oil, then zucchini, onion and garlic. Cook for about 10 minutes or until onion is tender and opaque, and zucchini is wilted. Then add tomatoes (if desired) and cook for another 5 minutes or until tomatoes are soft. In a small bowl, whisk together chicken stock and flour until thoroughly combined, then add to vegetables. Cook for another minute or two, until sauce is thickened. Add salt and pepper to taste.

In a large bowl, combine pasta, zucchini mixture, feta cheese, and cooked chicken (if desired) until combined. Pour into a 13x9 baking dish coated with cooking spray. Sprinkle mozzarella cheese over entire casserole and bake at 400 degrees for about 20 minutes, or until bubbly and lightly browned.