Preheat the oven to 350°F. Spray a 12-cup muffin tin with nonstick spray, or fill with paper liners.
In a medium-sized bowl, whisk together the dry ingredients, and then stir in the cranberries. In a separate bowl, whisk together the milk, eggs, oil (or butter) and orange zest. Add the wet ingredients to the dry, stirring just until blended (don't over-mix or your muffins will be tough!) Fill the prepared muffin cups about 3/4 full.
Bake the muffins for 15 to 20 minutes, until they're golden brown. Remove them from the oven, leave them in the pan for 5 minutes, and then transfer them to a rack to cool completely.
In a small saucepan (or microwave) stir together the glaze ingredients. Bring to a boil to dissolve the sugar. Stir until the sugar is dissolved. Dip the tops of the warm muffins into the glaze and set right-side-up on racks to dry.
Notes
For a sweeter muffin, use dried cranberries instead of fresh. Fresh will give them a more tart flavor.