Preheat oven to 325. Lightly butter 2 qt baking dish.
Into med bowl, sift together cocoa powder and flour. In large bowl, with mixer on on med/hi speed, beat eggs and sugar 5-10 minutes or until very thick and light yellow.
Reduce speed to low; add vanilla seeds, liqueuer and coca mixture. Mix just until combined. Slowly pour in butter; mix until combined.
Pour mixture into prepared dish set in a larger baking pan. Add hot tap water to pan to come halfway up side of dish.
Bake exactly 1 hour. A toothpick inserted 2 inches from side of dish will come out clean, the center will appear very under baked. Cool completely.