2 tablespoons olive oil
2 tablespoons butter, softened
2 pounds portobello mushrooms, in 1/4-inch slices (save the stems for another use) (you can use cremini instead, as well)
1/2 carrot, finely diced
1 small yellow onion, finely diced
2 cloves garlic, minced
1 cup full-bodied red wine
2 cups beef or vegetable broth (beef broth is traditional but vegetable to make it vegetarian; it works with either)
2 tablespoons tomato paste
1 teaspoon fresh thyme leaves (1/2 teaspoon dried)
1 1/2 tablespoons all-purpose flour
1 cup pearl onions, peeled (thawed if frozen)
Egg noodles, for serving
Sour cream and chopped chives or parsley, for garnish (optional)