Pre Heat oven to 375 Melt Butter and Chocolate in a double boiler over boiling water. In a separate bowl, beat eggs and add sugar. Combine with chocolate mixture. Add the Jack. Cut a circle of parchment or wax paper to place on the bottom of the spring form pan Butter the spring form pan. Place the circle of paper on the bottom of the pan and butter the top of the paper. Pour mixture into spring form pan Place in large baking pan and put the pan on the oven rack Add boiling water to about 1/2 to 2/3 of the way up the spring pan. Bake 50 - 60 minutes. The top should be wavy. Let it cool and the tort will collapse some, that's OK. Best when made the day before