Preheat oven to 375 degrees F and grease a 9×13 baking dish.
In a large dutch oven over medium heat, add the olive oil. Once hot, add onion and cook for 2-3 minutes, then add the garlic. Season with salt and pepper to taste.
Once onions and garlic are fragrant, add carrots and cook for an additional 3-4 minutes.
Lastly, add zucchini, summer squash, and broccoli and cook until all vegetables are tender. Remove from heat and set aside.
To make the sauce: In a medium-sized saucepan, add butter and flour. Stirring often, cook for 1 minute. Slowly whisk in milk and bring mixture to a boil. Cook for an additional 2 minutes, whisking continuously. Remove from heat and mix in salt, pepper, oregano, parmesan cheese, and red pepper flakes. Set aside.
In a medium-sized mixing bowl, combine cottage cheese and 1 ½ cups mozzarella cheese.
To assemble: Spread a thin layer of sauce in bottom of prepare baking dish. Place 3 (cooked!) noodles on top of sauce. Spread half the vegetable filling over the noodles, followed by half the cottage cheese mixture and 1 cup of sauce. Top with 3 more noodles and repeat previous layers once more, ending with noodles. Spread remaining sauce on top and sprinkle ½ cup mozzarella and ½ cup parmesan cheese.
Cover tightly with foil and bake for 25 minutes. Uncover and bake for an additional 20-25 minutes or until cheese is golden brown.
Allow lasagna to sit for 10 minutes before slicing and serving.
