Preheat the oven to 180º C and prepare a removable bottom round mold, about 20 cm in diameter. The easiest thing is to hook a sheet of baking paper into the mold to cover the base, and grease the sides with butter or oil.
Wash and dry the carrots, peel lightly with a peeler and grate very thinly in a bowl, until weighing 300 g. Mix with the zest of a half grated orange, or use tangerine or lemon, well washed.
Beat the eggs in a medium bowl with energy, by hand or, better, with a rod mixer, until they wait. Add carrot, sweetener (if used), salt and vanilla, and beat a little more.
Add the ground almonds, oats or protein, cinnamon and yeast, and beat at low speed until you get a homogeneous wet mass. Finish removing with a tongue to ensure there are no dry debris at the bottom.
Fill the mold, matching the top, and bake in the bottom half of the oven for about 35 minutes, watching well that it does not happen. Check that you are ready by clicking with a stick; You should go out with only a few miguitas.
Wait a little out of the oven before unmolding very carefully and leave cool completely on a rack Once cold, spread the yogurt or cheese and sprinkle with cinnamon.