Preheat oven to 350. Grease a 13-by-9-inch glass baking pan.
To make the cake, sift together flour, baking powder and salt in a small bowl. Combine butter and sugar in a large bowl. Beat with a mixer on medium speed until well blended. Add eggs. Add milk alternately with the dry ingredients, starting and ending with dry ingredients. Mix well. Stir in cranberries. Bake 30 minutes or until wooden pick inserted comes out clean.
To make the sauce, combine all ingredients in saucepan over medium low and
cook 10 minutes or until sugar is melted, stirring frequently. Pour hot over cake.