Pre-heat the oven to 350 degrees, and line a 10-inch springform pan or 10-inch cake pan with parchment paper and butter the sides.
Put the egg yolks into a medium mixing bowl and set aside. Put the egg whites into a small mixing bowl and beat until fluffy. Set the egg whites aside.
Add the olive oil, honey, coconut sugar, coconut milk, and almond extract to the egg yolks, and blend until smooth and creamy.
Add the flours, baking powder, baking soda, and sea salt to the wet ingredients and combine with a spatula – some lumps of flour are ok. When the batter is combined well, gently fold the whipped egg whites into the batter until just combined.
Smooth half of the cake batter into your springform pan, and sprinkle the cubed rhubarb over the top evenly. Smooth the other half of the cake batter over the top of the sprinkled rhubarb.
Arrange the stalks of rhubarb on the top of your cake how you like. I recommend halving or quartering your stalks of rhubarb length-wise, depending on the thickness of the stalks. If you leave them as is they get mushy and hard to manage/arrange in the pan. Making them thinner baked up prettier and the slices cut nicely. Bake at 350 degrees for 40-45 minutes, until the top is golden brown, and springs back to touch.
After the cake cools 10 minutes in the pan, you can turn it out to a cooling rack to cool completely. You can garnish the top with a drizzle of raw honey or dusting of organic powdered cane sugar when it is cooled.