In a bowl sifted flour with baking powder and salt. In another large bowl, stir together the butter and sugar about 2-3 minutes. Add egg and again stirred well. Add cognac, vanilla extract and stir well for 1 minute. Gradually add flour, milk and cream. Last pouring ground walnuts. The dough is mixed and distributed into greased muffin molds (12). Bake in preheated oven at 180 for 17-19 minutes. Remove and allow 10 minutes in this form, then transferred to a metal BBQ to complete their cooling. Each muffin covered with chocolate spread and sprinkle with coarsely ground hazelnuts.