Arrange the raspberries and blackberries in a small tray so that they are well spaced, then put them in the freezer. This will ensure that they won't damage too much when we add them to the batter.

Put chia seeds in the water and let all stand for at least 10 minutes.

Meanwhile place the hazelnuts in a pan warm over medium heat. Stir them often and turn off the heat when you start to smell the scent of toasted hazelnuts.

While the hazelnuts cool down, mix in a bowl the dry ingredients: flour, sugar and yeast.

Put hazelnuts in a food processor along with a pinch of salt, blend adding the oil a little at a time until you obtain a hazelnut butter.

Preheat the oven to 350°F.

Take the bowl with the dry ingredients, make a hole in the center and pour the hazelnut butter and chia "eggs". Stir the mixture with a spatula until it gets smooth.

Add to the batter the fruits straight from the freezer and mix gently with a spatula to distribute them evenly.

Prepare 10 mini muffins or cupcakes molds and pour one tablespoon of dough in each one.

Bake the cakes for 12 minutes. Remember to do the toothpick test to make sure the mini cakes are well done inside (the toothpick has to come out dry).

Let the mini cakes cool down before serving.