Soak the buckwheat groats in cold water for at least one hour or overnight.
Combine the drained buckwheat groats, water, almond milk, maple syrup, coconut oil, cocoa powder, cayenne, cinnamon, and sea salt in a large saucepan.
Bring to a boil, lower the heat, and let simmer for about 15 minutes, stirring regularly to prevent sticking. Taste to check if the buckwheat is cooked. It should be soft but still have a chewy texture. Porridge will be on the runny side but slightly thickens as it cools down.
Remove from heat, stir in the vanilla extract and let cool 3-5 minutes before serving. Top with coconut cream, roasted pecans, or your favorite toppings!
Chocolate buckwheat porridge will keep in the refrigerator for up to 4 days, reheat gently on the stovetop, adding more milk if needed to make it creamier again.