1. Make the cornbread: Preheat the oven to 400°. Grease a 10-inch cast iron skillet well with shortening.
2. Combine the cornmeal, flour, granulated sugar, baking powder, and salt in a large bowl. In a medium bowl, whisk together the orange juice, soymilk, and oil. Add the soymilk mixture to the flour mixture, stirring just until combined. Add the cranberries and orange zest and fold in, being careful not to overmix the batter.
3. Scoop the batter into the prepared skillet. Bake until lightly browned on top and a tester inserted in the center comes out clean, 40 to 50 minutes. Remove the cornbread from the oven and place on a rack to cool slightly.
4. Make the orange "butter": In a small bowl, whisk together the margarine, confectioners' sugar, and orange juice concentrate until smooth.
5. Serve the cornbread warm, spread with the "butter."