Pea Corn Salad

Ingredients

• 1 (15 ounce) can peas, drained
• 1 (15.25 ounce) can whole kernel corn, drained
• 1 (4.5 ounce) can sliced mushrooms, drained
• 1 hard-cooked egg, coarsely chopped - or more to taste
• 1/3 cup chopped onion, or more to taste
• 1/3 cup mayonnaise, or more to taste
• 1/4 cup sour cream, or more to taste (optional)
• 2 tablespoons chopped pickled pimento peppers
• 1 pinch salt and ground black pepper to taste