Spinach, Smoked Salmon And Cheddar Cheese Ball

Ingredients

• 1 c. butter, divided
• 1 c. flour, divided
• 1 qt. chicken stock
• 1/2 lb. sliced mushrooms, sauteed
• 1 c. heavy cream
• 1 1/2 c. Grey Poupon Dijon mustard, divided
• 1/2 lb. onion, chopped
• 1 1/2 Tbsp. olive oil
• 1 lb. frozen spinach, drained and chopped
• 1/2 c. sour cream
• 1 lb. smoked salmon, chopped
• 1/4 tsp. nutmeg
• 8 eggs, separated
• 2 c. half and half
• 1/2 c. Cheddar cheese, shredded