Oil two 8 x 8 inch cake pans or one larger rectangular pan (I think I used a 9 x 13 pan).
Combine and set aside:
1/4 cup plus 1 and 1/2 tablespoons flaxseed meal
3/4 cup boiling water
3 cups flour (cake flour would be best, but I used King Arthur All-Purpose Unbleached flour)
2 teaspoons baking powder (I used Hain Featherweight, which is made with potato starch)
1 tsp salt (RealSalt)
1 packet Kosher for Passover gelatin dessert mix (such as Ko-Jel or Kedem)--I used raspberry flavor Kedem
3/4 cup soft butter (you could substitute oil--I would probably reduce to 1/2 cup next time if subbing oil)
2 cups sugar (C & H/Domino's is pure cane sugar)
Blend into sugar mixture:
3/4 cup rice milk (Rice Dream Original Unenriched)
1/2 tsp vanilla (optional--I used more like 1 tsp homemade vanilla that was essentially a vanilla bean cut up and simmered in water)
Cooled flaxseed mixture
Stir together wet and dry ingredients and blend well, then pour batter into pan and smooth flat.
Bake at 350 degrees until toothpick comes out clean (about 50 minutes for a 9 x 13 pan).
Top with berries or whatever you like to put on cake. This time I made a Kosher For Passover vanilla pudding mix with half the amount of rice milk called for, added some K for P marshmallows while stirring over low heat, and then added pureed strawberries. It made a thin mixture that we spooned over each piece of cake and topped with a K for P marshmallow.