Place raisins in a bowl; cover with boiling water and let stand for 5 minutes. Drain, reserving 1 cup liquid; set raisins and liquid aside.
In a large bowl, cream butter and sugar. Add eggs; mix well. Combine the flour, cinnamon, baking soda and salt; add to creamed mixture alternately with reserved raisin liquid. Fold in raisins. Pour into a greased 15x10x -in. baking pan.
Bake at 375° for 16-20 minutes or until a toothpick comes out clean. Cool on a wire rack for 5 minutes. Meanwhile, in a small bowl, combine the glaze ingredients. Pour over warm cake and spread evenly. Cool before cutting.