Instant Pot Shepherd's Pie with Potatoes and Yams Recipe

Ingredients

• 1 cup low-sodium chicken broth
• 1 large yam, chopped
• 1 large russet potato, chopped
• 1 teaspoon Himalayan pink salt
• 1/2 cup milk
• 3 tablespoons butter
• 1 tablespoon vegetable oil
• 1/2 onion, chopped
• 2 cloves garlic, mashed
• 1 1/8 pounds ground beef
• salt and ground black pepper to taste
• 6 mushrooms, sliced
• 1 cup frozen corn
• 1 cup frozen green peas
• 1 crown broccoli, diced
• 1 carrot, chopped
• 1 stalk celery, chopped
• 1 (.87 ounce) package low-sodium gravy mix
• 1 tablespoon water, or as needed
• 1/2 cup shredded Cheddar cheese