In a large bowl, cream together the shortening and 1 cup of sugar until light and fluffy. Combine the flour, baking soda, salt, cinnamon, nutmeg, and cloves; stir into the creamed mixture until well blended. The mixture will be dry. Stir in the carrots, raisins and chopped walnuts. Pour into a well-greased pudding mold or coffee can. Cover the top with aluminum foil.
Place the pudding mold into a large kettle or Dutch oven filled with 2 inches of water. Cover the pan, and bring to a simmer. Allow the pudding to steam for 4 to 4 1/2 hours over low heat. Remove from the mold. Serve with warm lemon sauce.
To make the lemon sauce, mix together 3/4 cup of sugar, cornstarch and salt in a saucepan. Stir in hot water, butter, lemon juice and vanilla. Cook over medium heat until thickened. Serve warm over the pudding.