Preheat oven to 350F. Coat a 9 x 9" square with oil and dust with flour.
Combine cranberries and nuts in a small bowl. Set aside. In a saucepan, melt 2 Tbsp butter over medium heat. Stir in brown sugar, orange juice and cinnamon. Stir constantly for 3 minutes. Pour mixture into the pan and sprinkle with cranberry mixture.
Mix flour and baking powder in a bowl.
Bake for 40 minutes or until toothpick comes out clean. Cool for 5 - 10 minutes and invert on rack to finish cooling.
Mix the glaze ingredients - confectioner's sugar, melted butter and orange juice and drizzle over the cake.
In a large bowl, using a mixer beat sugar and remaining butter until creamy. Add vanilla, egg, buttermilk and flour mixture. Spoon over cranberries.