Corned Beef and Mushroom Pate - VeryVera

Ingredients

• 2 tbsp. butter
• 1/2 clove garlic, minced
• 1 small onion, finely diced
• 1/2 lb fresh mushrooms, finely diced (reserve 1 mushroom for garnish)
• 1 can corned beef, finely minced
• 8 oz sour cream, divided
• 1 tsp. ground mustard
• 1/2 tsp. salt
• 1/2 tsp. ground pepper