Preheat oven to 325°F.

Spray 9" cake pan with olive oil spray; dust with cocoa powder.

Cut a round of parchment paper & line the bottom of the pan. Then spray the parchment lightly.

Drain & rinse beans in a strainer. Shake off excess water.

Place beans, 3 eggs, vanilla, stevia, and salt into blender. Blend until completely liquefied (no lumps).

Whisk cocoa powder, baking powder, and baking soda.

Beat butter with sweetener until light and fluffy. Add remaining 2eggs, beating for a minute after each one.

Pour bean batter into egg mixture and mix. Finally stir in cocoa powder and water and beat on high for one minute, until smooth.

Scrape batter into pan and smooth the top. Grip pan firmly by the edges and rap on counter to remove air bubbles.

Bake for 40-45 minutes. Cake is done when top is rounded and firm to the touch.

Wait 10 minutes, turn out cake from pan, flip upright onto cooling rack.

Cool to room temperature, cover in plastic wrap. For best flavor, let sit overnight (8 hours).

For Frosting: Cream butter in a small bowl until fluffy. Powder Xylitol in a processor until a fine texture. Stir powdered sweetener into butter mixture with a scraper, then beat until smooth.

Slowly blend in the cocoa powder, vanilla, and sea salt. Beat in the half & half and the egg yolk.

Add Stevia 1/16 teaspoon at a time to desired sweetness.