Preheat oven to 450 degrees.

After the oven has been preheated, roast the vegetables until very soft and fork tender (about 30 minutes or so)

When the vegetables are finished cooking, puree in a food processor and set aside.

As the vegetables are cooking, bring 3 quarts of water to a boil in a large pot.

After the water has reached boiling, add 3 tablespoons of course salt, then add pasta and cook according to package directions (usually 6 to 9 minutes)

When pasta has been cooked, drain, and set aside.

In the meantime, in a large pan, melt butter over low heat

When butter has melted, add flour and cook until a roux forms (do not allow the mixture to brown)

Add 1 cup of milk a little at a time to the roux over medium heat, whisking as the milk is poured to form a thick sauce

Remove the milk mixture from heat, add the shredded cheese and 1/2 cup of the pureed vegetables, and stir until cheese is melted

Combine the milk-cheese-vegetable sauce with the pasta

Season to taste with salt and pepper

Serve immediately.