Spicy Spinach-Stuffed Mushrooms

INGREDIENTS

• 24 ounces, weight White Mushrooms
• 1 Tablespoon Olive Oil
• 1 Tablespoon Butter
• 1 whole Medium Onion, Diced
• 1/2 cup Panko Breadcrumbs
• Salt And Black Pepper To Taste
• 8 ounces, weight Cream Cheese, Softened
• 1/3 cup Sour Cream
• 1/2 cup Grated Sharp Cheddar Cheese
• 1/2 cup Grated Monterey Jack Or Farmer's Cheese
• 1 package (small) Chopped Spinach, Thawed
• 8 dashes Hot Sauce (I Used Choulula)