Preheat oven to 350 degrees F (175 degrees C).
Slice the Rhubarb (2) and mix it with Ground Cinnamon (1/4 teaspoon) and Honey (1 teaspoon).
Butter the 18 centimeter springform with Coconut Butter (1/4 teaspoon).
Mix Almond Flour (160 gram), Salt (1 pinch), and Baking Powder (1 teaspoon) together.
Separate the Egg (3) and set aside.
Whisk together the Egg Yolks and Honey (2 tablespoon).
With an electric mixer with a clean bowl and clean whisk attachment, beat the Egg Whites until firm.
Add Vanilla Extract (1 teaspoon) and Honey (1 tablespoon). Mix well until the egg whites mixture is firm.
With the spatula, gently fold together the egg whites mixture and egg yolks mixture.
Gently add in the almond flour mixture using a strainer and gently fold with spatula.
Add the rhubarb slices at the bottom of the springform.
Pour the mixture into the springform.
Bake for 25-30 minutes until golden and the toothpick comes out clean.
Let it cool down a little bit before you take it out of the form. Enjoy!