Pour the cake mix into a big bowl and mix the melted butter into cake mix until mixed well. Spread it across the bottom of a 9" springform pan. Spray pan with Pam first. Don't spread the crust on the sides, only on the bottom. Mix softened cream cheese, sugar and vanilla with electric mixer on medium speed until well blended. Add eggs, mix until blended. Pour over the crust. Bake at 350 for 40 minutes or until center is almost set. Cool. Refrigerate 3 hours or overnight. Makes 8 servings. If you use an 11" springform pan, make the crust same as above. However, double all the other ingredients. Bake 350 for 50-60 minutes. NOTE: Try experimenting with flavored coffee syrups. Or instead of 1/2 cup sugar, use 1/4 c. sugar and 1/4 c. chocolate syrup. Just make sure you use 1/2 cup of something sweet.(Or if you are doubling the recipe, make sure you use 1 cup of something sweet. NOTE: Cook at 325 for 1 hour--cake will not crack.