Mini Cheese Soufflés

Ingredients

• ¼ cup + 2 tbsp. grated Parmigiano Reggiano cheese
• 3 tbsp. butter + 2 tbsp. butter
• 3 tbsp. flour
• 1 ¼ cup heavy cream
• 4 large egg yolks, + 7 large egg whites
• 3 tbsp. dry sherry (optional)
• 6 oz. Gruyere cheese, shredded
• 2 tbsp. sour cream
• 1 ¼ cup kosher salt
• 1 tsp. Dijon mustard
• ½ tsp. mustard powder
• ¼ tsp. cayenne pepper
• ¼ tsp. cream of tartar