Slow Cooker Vegetable Stroganoff

Name: Slow Cooker Vegetable Stroganoff
Ingredients: 2 cups Vegetable Broth; 12 ounces, weight Sliced Fresh Mushrooms; 1 whole Yellow Onion, Coarsely Chopped; 1 whole Russet Potato, Washed Well And Coarsely Chopped; 1 whole Parsnip, Washed Well And Coarsely Chopped; 2 teaspoons Minced Garlic; ⅛ teaspoons Ground Black Pepper, More To Taste; 1 cup Frozen Green Peas; ¼ teaspoons Dry Mustard; 1-½ Tablespoon Worcestershire Sauce; 2 teaspoons Cornstarch; 1-½ cup Light Sour Cream (substitute Full Fat Or 2% Greek Yogurt If Desired)