Start off by cooking the egg noodles according to the package. Be sure to reserve 1 cup of the water from the pasta once done.
Next, place a large pan over low heat.
Toss in 4 tbsp of salted butter, and let it melt down.
Once the butter is melted, turn the heat to medium and sprinkle in the all purpose flour and whisk.
Slowly pour in the half & half, and whisk until lump free.
Reduce the heat to low, then add in the 8 oz of cheese.
Mix the cheese in with the sauce until well combined.
Now add in the mixed vegetables, onions, corned beef, and garlic.
Mix everything until well combined.
Next in a large mixing bowl (or pot ), combine the veggie & corned beef mixture, with the egg noodles.
Pour in 1/2 - 1 cup of the reserved pasta water into the mixing bowl.
Fold all the ingredients until everything is well incorporated.
Grab a 9 x 13 bake dish, and lightly oil or butter it.
Add the casserole mixture.
Bake the casserole for 25 minutes on 350 F.
Once done, let the casserole rest for 5-10 minutes.
Serve and enjoy!