Pureed carrots stand in here for cheese sauce. Slideshow: More Macaroni and Cheese Recipes
In a large pot of boiling salted water, cook the pasta until al dente, 2 minutes before the pasta is done, stir in the peas and cook 2 minutes, then drain.
In a medium heavy pot with a lid, simmer the carrots with the shallot, chicken broth, oil, 3/4 teaspoon salt and 1/2 teaspoon pepper until the carrots are very tender, about 20 minutes. In a food processor, pulse the carrot mixture until smooth. Season with salt and pepper to taste. Toss the pasta with the carrot puree and peas, then serve.