Prepare a large tube pan; line the bottom with brown paper and grease the pan and lining. Preheat oven to 275 degrees F. Cut butter and sugar together until it resembles cornmeal. Cover the pecans and dates with the flour (in large bowl); rub together so all pieces are well-floured. Dump sugar and butter on top; mix. Break in whole eggs (fewest possible) until you have the a wet mass, but not a batter. Add vanilla extract, and pour into prepared cake pan. Bake until done, 1 1 1/2 hours.