Heat oven to 350°F. Grease a 9x5-inch loaf pan and line with a parchment sling.
Massage orange zest into the sugar in a large bowl until fragrant and slightly damp.
Whisk in orange juice, oil, yogurt, beaten eggs, and vanilla until smooth.
In another bowl, whisk flour, baking powder, baking soda, and salt.
Add dry ingredients to the wet mixture. Stir gently until a few dry streaks remain.
Fold in cranberries and walnuts just until evenly distributed. Do not overmix.
Scrape batter into the pan and smooth the top. Sprinkle with turbinado sugar, if using.
Bake 50–60 minutes, until a toothpick in the center comes out with a few moist crumbs.
Cool in the pan 15 minutes. Lift out, then cool completely on a rack before slicing.