Preheat your oven to 350 ℉. If you have a convection setting, it is recommended for this cake as it is very thin and the convection setting will help bake more evenly.
Mill your soft white wheat berries into flour and set aside.
Add eggs and granulated sugar to your mixer, mix until smooth ribbon consistency.
In another bowl combine flour, baking powder, baking soda, all spices and salt. Stir until all combined.
Slowly sprinkle the flour mixture into your mixer while running. Be sure to scrape the sides and bottom of your bowl. Do not over mix here.
Prepare your sheet pan by spraying the bottom and sides with non-stick cooking spray. Press a piece of parchment into the bottom of the pan and spray again. **You want to make sure the entire bottom of the pan is covered with parchment. Pour your batter into the prepared sheet pan. Using a rubber spatula, spread the batter into the pan until smooth and the same depth all the way across.
Place into the preheated oven bake for 10-15 minutes. *The time can vary drastically on these based on your oven. Because these are a VERY thin batter, you want to check these frequently. Your cake is done when it springs back when touched in the center. If your finger print stays pressed into the center or the batter or it is still wet when touched add 2-3 additional minutes.
While your cake bakes, take your cotton tea towel and lay flat on the counter. Dust GENEROUSLY with sifted powdered sugar. As soon as your cake comes out of the oven, take a knife or rubber spatula and run it around the edges of the pan to loosen the cake. Flip the cake onto the dusted tea towel. If you flip it quickly, it will be less likely to break or bend while flipping.
Carefully remove the Parchment paper from the back side of the cake. Starting on the short side of the cake, fold the end of the towel around the cake and roll into the towel. Place into the fridge until completely cooled. **I have had the best results with refrigerating overnight.