Preheat the oven to 200 degrees Celsius. Align the hazelnuts in a baking pan in a single layer. Put it in the oven for 10 minutes. Put roasted hazelnuts on one-half of the clean kitchen cloth and cover them with the other half. Roll them with your hand gently until the brown shell falls off. Put the peeled hazelnut into a kitchen mixer and grind them until you get smooth hazelnut mixture (similar to hazelnut spread). Add cocoa powder, sugar powder, salt and oil. Mix it together for one minute so that all ingredients are well mixed. If the mixture is too thick, add some oil.