Chicken Noodle Casserole

This is another Cook's Country "recipe makeover". This did come out nice and tasty, but it was also fairly time-consuming and labour-intensive. For me, the poor deliciousness:effort ratio means that this isn't one I'm likely to make again. If I ever do make it again though, I'd probably make a few changes. The recipe below reflects the "what I'd do next time" version rather than what I actually did this time.

Chicken Noodle Casserole
Adapted from Cook's Country June/July 2015
8 oz. wide egg noodles
1 Tbsp. + 1 tsp. coarse sea salt
1 Tbsp. oil
1 red bell pepper, chopped
227g cremini mushrooms, chopped
1 onion, chopped
2 carrots, chopped
1 rib of celery, chopped (optional)
2 cloves of garlic, minced
1 1/2 tsp. fresh thyme, minced
3 Tbsp. cornstarch
3 c. chicken broth
1 (12 oz.) can 2% evaporated milk
1 lb. boneless, skinless chicken breasts
1 1/2 c. frozen peas
1 tsp. pepper
200g light cheddar, grated
20 reduced-fat Ritz Crackers, crushed

1. Boil pasta in 2L of water and 1 Tbsp. salt until molto al dente. Drain and run under cold water until pasta is cool to the touch. Set aside.
2. Cook bell pepper, onion, carrots, celery, and garlic in oil with 1/4 ts. salt until beginning to brown. Stir in thyme and cook for an additional minute or so. Set aside.
3. Whisk cornstarch with 3 Tbsp. broth.
4. Combine evaporated milk and remaining broth and bring to a boil over high heat. Add chicken and reduce heat to medium-low. Cook until chicken registers 155F (about 10 minutes). Transfer chicken to plate.
5. Whisk cornstarch mixture into sauce, bring to a boil, and cook until thickened. (This should only take a minute or so.) Remove from heat.
6. Shred chicken and stir back into sauce. Add sautéed veggies and noodles. Add frozen peas, 3/4 tsp. salt and 1 tsp. pepper. Stir to combine. (In the original recipe, the grated cheese was added as soon as the sauce came off the heat to create a cheese sauce base for the casserole. TF and I found that the cheese flavour didn't really come through at all that way though. I think a cheese topping/crust would make the flavour a bit more distinct, so I'll try it that way next time.)
7. Toss cheese with crushed crackers. Top the casserole with the cracker mixture.
8. Bake at 425F for 15 minutes.
9. Allow to cool for 10 minutes before serving.