Pork Tenderloin with Creamy Dijon Sauce

INGREDIENTS

• 1 tablespoon extra-virgin olive oil, or more as needed
• 2 1/2 pounds whole pork tenderloins
• salt and black pepper to taste
• 1/4 teaspoon garlic powder, or to taste
• 1 onion, chopped
• 1 (8 ounce) package sliced fresh mushrooms
• 1/4 cup white wine
• 1 (10.75 ounce) can condensed cream of mushroom soup
• 2 tablespoons Dijon mustard
• 1/4 cup sour cream