1. In a 1- to 1½-quart saucepan bring the honey to a boil over moderate heat, stirring almost constantly with a wooden spoon. Stir in the cinnamon, cloves, nutmeg and baking soda and set aside to cool to room temperature. In a large bowl, cream the 4 tablespoons of butter and the sugar together by mashing and beating them against the sides of the bowl with a large spoon until they are light and fluffy.
2. Then beat in the egg yolks, one at a time, and stir in the cooled, spiced honey. Combine 1¾cups of the flour with the salt and baking powder and beat them into the sugar-and-egg mixture, ¼ cup at a time. Combine the raisins, currants and walnuts in a separate mixing bowl and toss them with the remaining ¼cup of flour until each piece is coated. Fold into the batter.
3. Preheat the oven to 300°. Beat the egg whites in a large bowl with a whisk or a rotary or electric beater, until they form stiff peaks on the beater when lifted out of the bowl. With a rubber spatula, gently fold the egg whites into the batter, using an over-and-under folding motion.
4. With 2 tablespoons of the softened butter, coat the bottom and sides of a 9-by-5-by-3-inch loaf pan. Coat both sides of a sheet of brown paper with the remaining table-spoon of butter and line the bottom and sides of the pan with it. Pour the batter into the pan and bake in the center of the oven for 1½ hours, or until a tooth pick or cake tester inserted into the center comes out clean.
5. Insert a knife between the paper lining and the pan, loosen the cake and invert it, with the paper, onto a cake rack. Peel off the paper and let the cake cool to room temperature, then cover loosely with wax paper and set aside for 1or 2 days at room temperature before slicing.
