Bake in greased and floured 11 x 15 x 1" sheet cake pan for 30 minutes at 375. Add oil, beets, cocoa and pudding, mix well. Hidden Secret Brownies (The New Frontier) - “The Pioneer Woman”, Ree Drummond on the Food Network. Preparation. If you buy fresh beetroot, you have two options: either peel, boil, and puree it, or peel and grate it. Blend in vanilla, flour, soda and salt. DIRECTIONS. If you buy ready cooked beetroot, then you simply puree it in a food processor. Beat together eggs and sugar.