Classic Stuffed Mushroom With Sausage

Ingredients

• 18-20 white button mushrooms, stems removed and chopped
• 2 tablespoons butter
• 1 small white onion, diced
• 1 celery stalk, diced
• 1 tablespoon olive oil
• 2 large garlic cloves, minced
• Kosher salt
• freshly ground black pepper
• 1 teaspoon paprika
• ¼ cup chicken stock
• 2 tablespoons dry sherry
• 1 sleeve Ritz crackers, crushed
• 8 ounces sausage, diced (optional)
• Parsley and lemon, for garnish