Preheat oven to 350°; grease and flour an 8x4 inch loaf pan.
In the bowl of a food processor fitted with a steel blade, combine the cranberries and sugar; pulse to coarsely grind; set aside.
In a big bowl, combine the flour, baking powder, spices, and salt; add in the orange zest and walnuts; toss to blend.
In a small bowl, combine the orange juice and eggs; beat with a whisk until frothy; add in vanilla and cranberry mixture; stir to combine, then pour over dry ingredients and drizzle with melted butter.
Stir with a large spatula just until the batter is moistened and the cranberries are evenly distributed.
Pour batter into loaf pan; bake in the center of oven for 45-50 minutes, until a pick comes out clean.
The top of the loaf should be crusty and golden.
Turn loaf out of pan onto a rack, then turn it right side up to cool completely.
Wrap tightly in plastic wrap and let stand at room temperature overnight before serving.