1 ¼cups(390 g) maple syrup (preferably light-colored)
¼cup(55 g) strained lemon juice
for decorating (optional): lemon wedges, bee pollen, edible flowers
Make the frosting and chill until firm while you prepare the cake layers.
Position a rack in the center of the oven and preheat to 350ºF. Rub the sides of two 8-inch round cake pans (with 2-inch high sides) with the coconut oil. Line the bottoms with rounds of parchment paper cut to fit. Alternatively, use 9-inch cake pans for thinner layers.
In a very large bowl, whisk together the coconut yogurt and lemon zest to combine. Let sit for 15 minutes to draw out the lemon flavor and to bring the yogurt up to room temperature.
Meanwhile, sift the cassava, coconut, and tapioca flours together with the baking powder, baking soda, and salt into a medium bowl.
One at a time, whisk the eggs into the yogurt mixutre. Whisk in the avocado oil until combined and emulsified. Whisk in the maple syrup, then the lemon juice.
Dump the sifted flour mixture into the yogurt mixture and whisk until smooth; the batter will start out very thin, but it will thicken up as the flours absorb moisture.
Pour even layers into the prepared pans (about 710 grams each by weight) and smooth the tops.
Bake the cake layers until the tops are golden with some cracks, the edges pull away from the sides of the pans, and a toothpick inserted near the center comes out with moist crumbs, 30-35 minutes.
Place the cakes on a wire rack and let cool completely. Once cool, wrap tightly and chill (or freeze) until firm; this will make them easier to handle and frost.
Once the cakes are chilled or frozen, loosen the edges of the cakes from the pans using a small, offset spatula. Turn the cakes out onto plates and peel away the parchment.
To frost, place one cake layer on a serving plate or cake stand. Spread a healthy layer of frosting over the top, making it as even as possible. Place the second cake layer over the frosting and smush it down slightly.
Now spread a healthy layer of frosting over the top of the cake. If frosting the sides, pull the frosting down the sides to cover. Smooth with an offset spatula. This is your crumb coat; you can leave the sides with a thin layer as I did here if you like. Otherwise, chill or freeze the cake until the frosting is firm, and repeat frosting the top and sides to make a thicker layer. You can repeat this once more for a third layer if you like. Smooth the top of the cake.
If you want to get fancy, top the cake with lemon slices cut into quarters. Pipe more frosting around the edges using a large star tip, then use a small start tip to pipe on more goodness. Sprinkle with bee pollen if you like, and top with edible flower petals, if using.
Chill the cake until ready to serve. If you’re waiting more than a few hours, place the cake in a box to keep the frosting from drying out.
To cut clean slices, dip a large, sharp chef’s knife in hot water, then wipe dry between each cut.
The frosting will stay firm at cool room temperature for an hour or two, but it does melt easily if placed in direct sun or if the room is warm. Ideally, chill until ready to serve, then slice and let slices come up to room temperature before serving. This will ensure gooey frosting and soft, pillowy cake.
The cake is best within 1-2 days of baking, but leftovers will keep, refrigerated airtight, for up to 3 days. Or freeze leftovers for up to 1 month. Bring to room temperature before enjoying.
Make-ahead: The cake layers can be made 1 day ahead, wrapped tightly, and refrigerated. Or freeze airtight for up to 1 month. The frosting can be made several days ahead and refrigerated until needed.Paleo Lemon Sheet Cake: Want to skip all that layer cake fuss? Bake the cake in a 9x12-inch baking pan lined on the bottom and sides with parchment paper. Increase the baking time as needed. Once the cake has cooled, invert it onto a large cutting board, peel away the parchment paper, then invert it right side up on a serving platter. Slather the top with paleo cream cheese frosting and top with your decorations of choice, if using.Nutritional values are for the cake only; 1 of 16 servings.