Sift flour with baking powder and salt. Cream butter; add 1 1/2 c of the sugar gradually and blend until light and fluffy. Beat in egg yolks. Add chocolate and vanilla. Add flour alternately with milk, mixing well after each adition. Beat egg whites until stiff but not dry; add 1/2 c sugar and fold into batter. Turn into pans and bake 35 minutes. Cool. Pour 2 Tbsp Tia Maria over each layer and frost with Florence icing. Dust sides with chopped nuts. Florence Icing 4 Tbsp butter 2 c sugar 1/2 c milk 2 oz bitter chocolate Melt butter in a saucepan; add sugar and milk. Bring to a boil stirring constantly then cook over low heat 10 minutes or until temperature reaches 236 degrees. or 115 c. Melt chocolate; add Tia Maria. Stir into butter mixture. Remove from heat and beat icing until thick enough to spread. If icing hardens before cake is frosted, soften with a little hot water.