Spinach Casserole

Ingredients

• 3 c. Rice Chex, crushed to 1 1/2 c.
• 1 tsp. onion powder
• 3 Tbsp. margarine, melted
• 1 (8 oz.) pkg. cream cheese
• 1 (5 oz.) can evaporated milk
• 2 tsp. lemon juice
• 3/4 tsp. season salt (or to your taste)
• dash of white pepper (to your taste or leave out)
• 1 (8 oz.) can sliced mushrooms, drained (reserve 1/3 c. liquid)
• 1 egg, well beaten
• 1 (10 oz.) pkg. frozen chopped spinach, cooked and drained