Cook noodles according to package directions. Drain.
8 ounces wide egg noodles
Heat a large skillet over medium heat. Put oil in the pan and cook the onion and carrot for about 6 minutes or until carrot is almost tender, stirring occasionally. Sprinkle with flour and cook 1 minute, stirring constantly. Gradually whisk in milk, raise heat to medium-high and cook for 5 minutes, stirring constantly with a whisk until slightly thick.
2 tablespoons olive oil, ½ cup yellow onion, ⅓ cup carrot, 2 tablespoons flour, 2 ¾ cups milk
Stir in cream cheese, mustard, salt, and pepper and cook 2 minutes, stirring constantly.
4 ounces ⅓ less fat cream cheese, 1 tablespoon Dijon mustard, ¼ teaspoon salt, ½ teaspoon black pepper
Preheat broiler.
Reduce heat to medium, stir in peas, corn, ¼ cup Parmesan cheese, and tuna. Add pasta and heat through. Top with remaining ¼ cup Parmesan cheese.
½ cup frozen peas, ½ cup frozen corn, ½ cup grated Parmesan cheese, 2 cans tuna in water, drained and flaked
Broil 3 minutes or until golden and bubbly. Let stand 5 minutes before serving.