1. Preheat oven to 300 degreesF. Combine crackers, melted butter, and 2 tablespoons sugar. Press into bottom and 1 inch up sides of a 9-inch springform pan; set aside. In bowl beat 1 package cream cheese with electric mixer until smooth. Beat in peanut butter and 1/4 cup sugar until combined. Fold in 1 lightly beaten egg; set aside.
2. In saucepan stir chocolate over low heat until melted and smooth. Remove from heat. Cube remaining cream cheese; add to chocolate. Stir to combine. Stir in milk and vanilla until smooth. Fold in 2 lightly beaten eggs. Spread half the chocolate mixture into pan. Carefully spread all the peanut butter mixture over layer. Evenly spread remaining chocolate mixture.
3. Bake 45 minutes or until top is set when lightly shaken. Outer 2 inches of the top will be slightly puffed and dry-looking; center will look darker and wet. Cool in pan on rack 15 minutes. Use a small sharp knife to loosen crust from sides; cool completely on rack. Cover; chill 4 hours. Let stand at room temperature 15 minutes before serving. Sprinkle with peanuts. Makes 16 servings.