Preheat the oven to 180°C (356°F).
In a bowl, mix oat flour, almond flour, baking powder, and a pinch of salt.
In another bowl, combine eggs, Greek yogurt, oligosaccharide syrup, vanilla extract, and coffee. Mix well.
Combine the wet and dry ingredients and mix thoroughly.
Add walnuts or other desired nuts to the batter.
Line a pan with parchment paper and pour in the batter.
Bake in the preheated oven for 25–30 minutes.
Let it cool, then cut into bite-sized pieces.