Preheat oven to 350F (not fan assisted), with rack in the centre of the oven. Grease a 9x5-inch loaf pan and set aside.
In a large bowl, whisk together the flour, sugar, baking powder, baking soda and salt. Cut butter into 4 pieces and add to the dry ingredients. Using your fingertips, rub the cold butter into the flour mixture, breaking it up as you go, until you have an evenly crumbly mixture resembling corn meal.
Remove the zest from In a 2-cup measuring cup, combine the orange juice, orange zest and well beaten egg. Pour the orange juice mixture all at once into the dry ingredients. Using a wooden spoon, mix together just enough to dampen all the flour. Gently stir in the cranberries.
Spoon batter into a greased 9x5-inch loaf pan and bake in preheated oven for about 1 hour, or until a tester inserted in the centre comes out clean. Allow to cool in the pan for 10 minutes, then run a knife around the side of the pan and turn out/remove from pan and allow to cool completely on a cooling rack.
Prepare glaze by stirring together the glaze ingredients until smooth. Place a piece of waxed paper or paper towel under the cooling rack to catch drips, then spoon the glaze over the cooled loaf, spooning it onto the top and letting it run down the side. Allow to stand until it sets before slicing.
*Starting with 1 large, fresh orange, first remove the zest from the orange, then squeeze all the juice from the orange into a measuring cup. Add enough additional water until it measures 3/4 cup.**Note that the recipe specified that the egg be "well beaten" before adding to the other liquid ingredients. This is because we want to stir the batter as little as possible after combining the wet and dry ingredients. If the egg isn't beaten beforehand, you would have to do a lot more stirring to mix it in. Pre-beating it prevents over-mixing.Loaf keeps well at room temperature for about 2 days. I like to just wrap the cut end, as the glaze can get moist if wrapped tightly. Loaf can also be frozen, well wrapper, up to 2 months.Be sure to read the “Ingredient and Cook's Notes" (above the recipe card!), where I share more detailedtips, variations and substitution suggestions for this recipe!