First place the lemon(s) whole (do not cut, prick, or peel) in a small saucepan and cover with water. Bring to a boil, then reduce heat and let simmer, partially covered, for about 15 minutes. Remove lemon(s) and let cool enough to handle.
While preparing the lemons, preheat oven to 350 degrees, and prepare a 9” springform pan (works best for this cake).with strips of parchment. It is also helpful to wipe a smidgen of oil on the bottom and sides of the pan, but if you do not want to do this, line with strips of parchment.
Add dry ingredients (flour, almond meal, sugar, baking powder, baking soda, and salt) to a mixing bowl.
In a blender, add the nut butter, milk, maple syrup, and vanilla. Then, holding the lemons over a small bowl (to catch any juices), cut the lemons in half. Remove any seeds from the lemon and discard, and trim any stem off the lemon(s). Add the whole lemon (and any juices that came out when slicing) to your blender. Puree mixture until very smooth.
Add this blended mixture to the dry, and stir through until just well combined.
Transfer mixture to prepared springform pan and place in preheated oven. Bake for 30-33 minutes, or until a toothpick inserted in the centre comes out clean. Let cool on a cooling rack.
Prepare Almond-Maple Sauce (recipe follows) or the Sweet Potato Caramel Sauce (recipe in Let Them Eat Oil-Free Vegan ebook).