8-9 oz. Pappardelle’s Gluten-Free Porcini Mushroom Large Trumpet
2 Tbsp. unsalted butter
1 tsp. salt, divided, plus more to taste
1 tsp. black pepper, divided, plus more to taste
1 lb. beef sirloin, trimmed of fat & thinly sliced into bite-sized pieces
8 oz. sliced mushrooms (Cremini, White Button or Porcini)
1 sweet onion, diced
3 cloves garlic, minced
2 Tbsp. tomato paste
1 Tbsp. Worcestershire sauce
4 cups low-sodium beef stock
1 cup sour cream
Fresh parsley, chopped, for garnish