Nan's Recipes: California Burgers

Ingredients

• 2 tablespoons butter
• 2 or 3 scallions
• 1 small clove garlic
• 4 ounces mushrooms
• 1 lb ground beef
• 1 1/2 cup shredded Gruyere
• 1 tablespoon ketchup
• salt to taste
• a shake of hot sauce, if desired