Brown beef in a skillet with a swirl of olive oil, or warm up meat if already cooked
In a microwave-safe large bowl (such as an 8-cup Pyrex pourable measure), combine water and casserole sauce mix. This mix (see recipe) has beef bouillon, seasonings, cornstarch for thickening, and dry milk for a creamy base. It replaces use of canned cream of mushroom soup.
Whisk the water and sauce mix and microwave at three-minute intervals until it begins to thicken. Whisk between each cook time. Continue cooking in microwave for one-minute segments, watching so it doesn't bubble over.
Add thickened sauce to beef in skillet. Bring to a bubble and add pasta, keeping heat high enough to cook the pasta. Cook for 8-11 minutes, checking texture of pasta toward the end. Add up to a cup of hot water during cooking if the mixture gets too thick.
Add Worcestershire sauce and sour cream or plain yogurt just before serving.
Serves six with veggies and homemade bread.