Step 1

In 2-quart saucepan, heat butter over medium-high heat. Add mushrooms, salt and pepper; cook 3 to 5 minutes, stirring frequently, until tender.

Step 2

Add beef broth, egg noodles and meatballs; heat to boiling. Reduce heat to medium; simmer uncovered 9 to 11 minutes, stirring occasionally, until liquid is mostly absorbed. Remove from heat; let stand 5 minutes.

Step 3

Stir in sour cream; serve immediately.