Preheat oven to 400 degrees F. Spray a baking dish with nonstick spray. Line a baking sheet with aluminum foil.

In a large bowl, combine corn, peppers, squash and onions with salt and pepper. Whisk together olive oil and vinegar, then add over top and toss to coat. Spread on the baking sheet and roast for 25-30 minutes.

When the veggies are almost finished roasting, bring water to a boil and prepare pasta according to directions – shaving 1-2 minutes off of the cooking time.

To make the cheese sauce, heat butter in a medium saucepan over medium heat. Once sizzling, add flour and whisk constantly to create a roux, until golden and bubbly, about 2 minutes. Pour in milk and whisk constantly, stirring until the mixture slightly thickens. Reduce heat to low and add in 6 ounces of the havarti and cheddar and all of the parmesan, along with the minced garlic. Stir until cheese melts and sauce is thick. Taste and season with a bit of salt and pepper if desired. I usually add a pinch of nutmeg.

Add cooked pasta and vegetables to a large baking dish, tossing to coat. Pour cheese soup over top and stir to evenly distribute. Cover the top the the remaining havarti and cheddar, then the breadcrumbs. Bake for 30-35 minutes, or until cheese is golden and bubbly on top. Serve with sliced avocado if desired.