Sift buckwheat flour and rice flour together with baking powder.

Add salt and sugar to the sifted flours.

Create a well in the center of the flour mixture.

Pour in egg yolk, milk, and oil into the well.

Whisk the wet ingredients until well combined with the dry ingredients.

In a separate bowl, whisk the egg white until stiff peaks form.

Gently fold the whisked egg white into the batter.

Melt butter in a heavy pan over medium heat.

Pour some batter into the hot pan and cook until bubbles appear on top.

Flip the pancake and cook until golden brown.

In a saucepan, add the frozen blueberries and raspberries.

Gently heat the berries until they break down into a sauce.

Serve the pancakes with berry sauce, ricotta or plain yogurt, and maple syrup.