Heat the oven to 350°F (175°C). Grease a 9x5-inch loaf pan and line it with parchment paper, leaving a little overhang on the long sides so the loaf lifts out easily.
Whisk the dry ingredients: in a medium bowl, whisk together the flour, baking powder, baking soda, and salt. Set aside.
Cream the butter and sugar: in a large bowl, beat the softened butter, granulated sugar, and orange zest on medium speed until light and fluffy, about 3 minutes. Beat in the eggs one at a time, then beat in the sour cream, orange juice, and vanilla until smooth.
Add the dry ingredients: with the mixer on low, add the flour mixture and mix just until no dry streaks remain. Do not overmix — a few small lumps are fine.
Fold in the cranberries: toss the fresh cranberries with the remaining 1 tablespoon of flour, then fold them gently into the batter with a spatula. The flour coating keeps the berries from sinking to the bottom.
Bake: pour the batter into the prepared pan and smooth the top. Bake for 55-65 minutes, until a toothpick inserted in the center comes out clean with a few moist crumbs. If the top is browning too quickly, tent the pan loosely with foil after 40 minutes.
Cool: let the loaf cool in the pan for 15 minutes, then lift it out using the parchment overhang and cool completely on a wire rack, about 1 hour. Glaze only once the loaf is fully cool.
Make the glaze: whisk the sifted powdered sugar with 2 tablespoons of orange juice and the orange zest until smooth and pourable. Add the remaining juice a teaspoon at a time if the glaze is too thick. Drizzle over the cooled loaf, letting it drip down the sides.
Make the sugared cranberries: in a small saucepan, simmer the water and 1/4 cup of sugar until the sugar dissolves. Remove from the heat, stir in the cranberries, and let them stand for 5 minutes. Lift them out with a slotted spoon, roll them in the remaining 1/4 cup of sugar, and dry on parchment for 30 minutes. Scatter over the glazed loaf before serving.