Never Fail Fudge

Ingredients

• 1/2 c. cocoa
• 1 stick butter
• 1 lb. powdered sugar
• 1/4 c. milk
• 1 tsp. vanilla
• 1/2 c. chopped nuts
• 1 1/2 c. sugar (extra fine if available)
• 1 lb. Ricotta *
• 1 lb. Philadelphia brand cream cheese *
• 1 pt. sour cream
• 4 medium eggs
• 1 tsp. lemon juice
• 3 tsp. cornstarch
• 2 tsp. vanilla
• 3 Tbsp. flour
• 1 cube butter (not margarine), melted and cooled