In a large saucepan, bring 2 cups water to a boil. Reduce heat to medium and add butter, sugar, raisins, instant coffee, cinnamon, allspice, nutmeg, cloves, and salt. Stir mixture occasionally and let simmer for 15 minutes. Remove from heat.

Dissolve baking soda in 1 cup cold water. Add to raisin-spice mixture. Add flour, one cup at a time, stirring well after each addition. Pour batter into a greased 9x13 inch baking pan.

Bake for about 20-30 minutes, or until a toothpick inserted into center of cake comes out clean.

Let stand at room temperature until completely cool. Dust with powdered sugar, if desired.

To freeze cake: Do not dust with powdered sugar. Leave whole or cut into portions. Wrap well in freezer paper.

May be frozen for up to 2 months. Defrost at room temperature.