- Preheat the oven at 180C and line an 8inch square or rectangular tray with parchment paper. In a large bowl add the sugar and vegetable oil and beat well until pale. Add the buttermilk, vanilla extract, lemon juice, yogurt and mix well. Add red food colour to this. Sift in the flour, cocoa powder and the baking soda and mix until everything is well combined. Transfer the batter into the prepared tray. Bake For 15-20 minutes or until a skewer inserted comes out clean. Once the cake has cooled down completely, using a 3 inch circular ring cut 3 layers for the cake. Frost and assemble the cake with your choice of frosting. Once frosted, decorate the eggless red velvet bento cake however you like.