Preheat the oven to 375 degrees F. Grease a 9x13 baking pan.
Combine water, raisins, and shortening in a medium saucepan. Boil over medium heat, covered, for 20 minutes. Remove from heat, remove the lid, and let cool for 10 minutes.
While the raisin mixture is boiling, whisk together the flour, sugar, baking soda, baking powder, salt, cinnamon, nutmeg and cloves in a large bowl.
Pour the slightly cooled raisin mixture over the dry ingredients and stir with a wooden spoon until mostly combined and moistened (the batter at this point will have the consistency of a paste). Add the beaten eggs and again stir with a spoon, until thoroughly combined. Stir in the chopped walnuts.
Spread the batter into the prepared pan and bake for 25 to 30 minutes, until deeply browned and a toothpick inserted into the center comes out mostly clean with some moist crumbs attached.
While the cookies are baking, prepare the glaze by whisking together the powdered sugar and warm water in a small bowl. As soon as you take the pan out of the oven, drizzle the glaze over the cookies and quickly spread into an even layer.
Cool to room temperature before serving. Store leftovers in an airtight container at room temperature for up to 4 days.