Cream together butter, flavorings, and sugar. Beat in eggs and vanilla. Add dry ingredients alternately with the milk. Mix well. Place in greased 9x13 pan. This will be a thick batter. Now mix together rhubarb, jello and sugar. Combine and spread over the cake batter. Press into the batter. Bake at 350 degree oven for 40-45 minutes until top is golden brown and center is set. This is great with ice cream or whipped cream.