For the Cake:
2 cups water
3/4 cup raisins
1/2 cup vegetable oil
2 cups all-purpose flour
1 cup granulated sugar
1 1/2 teaspoons pumpkin pie spice
1 teaspoon baking soda
1/2 teaspoon fine salt
1 large egg, lightly beaten
3/4 cup walnuts, very finely chopped (optional)
For the Frosting:
8 ounces cream cheese, room temperature
1/4 cup unsalted butter, room temperature
2 1/4 cups powdered sugar
1/4 teaspoon fine salt
To make the Cake:
