Preheat the oven to 350℉. Coat an 8x4-inch loaf pan with cooking spray (the kind that includes flour) and set aside.
Add the dry ingredients (flour, baking powder, salt, and sugar to a large bowl and give it a stir with a whisk. Then add the orange zest, working it into the sugar mixture with your fingers. This helps distribute the oils from the zest more evenly and to release them into the sugar for the best flavor.
In a glass measuring cup, whisk the wet ingredients together till will blended (vegetable oil, eggs, orange juice, milk, and vanilla). Pour into the dry ingredients and mix just until blended - do not overmix.
Next, toss the cranberries with about a teaspoon of flour. (This will help keep them from sinking to the bottom of the bread.) Gently fold the cranberries into the batter.
Pour the batter into the prepared pan and place in the preheated oven. Bake for 45-55 minutes, or till a toothpick inserted in the center comes out clean.
Remove the bread from the oven and allow it to cool completely in the pan.
When the bread is nearly cooled, make the glaze by whisking a tablespoon of freshly squeezed orange juice with one cup of powdered sugar that has been sifted. If the glaze is too thick to pour, add more orange juice till you reach your desired consistency. (Another tablespoon usually does the trick, but you may find you need more or less.)
Remove the cooled bread from the pan and pour the glaze over the top, evenly coating the bread and letting it drip down the sides. The glaze will firm up as it cools.
Slice and serve, or store covered till you're ready to enjoy it (we keep it on a serving plate and cover it with plastic wrap).The bread keeps for about three days.