Preheat oven to 375F and move the rack to the top third of the oven.
Prep all recipe ingredients. For the melted butter, I suggest microwaving it in a small bowl and setting it aside until needed.
Cook the egg noodles for a couple minutes less than the package directions indicate. Drain and add them to a 9x13 casserole dish.
Meanwhile, add the oil, onion, and celery to a skillet over medium-high heat. Cook for 5 minutes.
Add the garlic to the skillet and cook for about 30 seconds, then transfer the skillet contents to the casserole dish.
To the same skillet, over medium heat, add the cream cheese (microwave it for 20-30 seconds if it isn't soft yet), cream, chicken broth, Dijon mustard, Worcestershire sauce, and a bit of salt & pepper. Stir/whisk nearly constantly until the cream cheese has melted into the sauce (about 5 minutes). Don't let the sauce get too thick (it should be similar to Alfredo sauce). If the sauce seems a bit too thick, add in another splash of cream. The sauce will thicken more as it bakes.
Turn the burner off and stir in the cheddar and parmesan until melted.
Add in the peas and tuna (I use a fork to flake it right in the can after draining it), then pour the skillet mixture over the noodles. Toss until well coated and spread it in an even layer.
Add the crushed Ritz crackers to the bowl that has the melted butter and mix well.
Top the casserole with the Ritz topping and bake uncovered for 20 minutes.