Cream butter and sugar until light. Beat in eggs. Combine flour, baking powder, soda, salt, cinnamon and allspice. Add dry ingredients to creamed mixture alternately with beer. Mix until blended. Stir in walnuts and raisins.
Turn into well greased and floured 2 quart pudding mold. Place in crockery part of pot. Cover top of mold with 4 or 5 layers of paper towels. Place lid LOOSELY on crock pot. Cook on High allowing 3 1/2 hours for 3 quart pot and 4 hours for 4 1/2 quart size.
Cool on rack 10 minutes, then turn out of pan. Serve warm with Hard Sauce or ice cream. Makes 1 cake.