A method for preparing a biomass dough by a baking method, in which method the ingredients of the biomass dough are mixed with a gluten-forming adhesive and are moistened, whereby the gluten proteins of the gluten-forming adhesive form a mesh-like structure that binds the ingredients of the dough to form a solid dough mass. The invention also relates to a fuel briquette which is a product compressed from a biomass dough made by a baking method and cut into a fixed length, and is intended to be burnt for the purpose of energy production.