Heat oven to 350°F. If your pecans are untoasted or if they’re labeled toasted but don’t taste very crisp or toasty, toast them now. Place pecans on a small baking sheet in the oven for 6 to 8 minutes, or until they smell fragrant. Remove and roughly chop, then set aside.
Coat a loaf pan (8½ by 4½ or 6-cup volume) with butter or nonstick spray. For easier removal, you can line the bottom and two long sides with a sling of parchment paper.
Place sugar in a large bowl, and zest oranges into it. Use your fingertips to rub the zest into the sugar, breaking it up a bit and releasing more fragrance.
Cut oranges in half and juice them into a 1-cup measure; I get between 1/3 and 1/2 cup. Spoon in sour cream until the juice reaches the 1-cup line; whisk to combine.
Whisk butter and egg into zest-sugar mixture. Whisk in orange juice-sour cream mixture. Sprinkle surface of batter with salt, baking powder, and baking soda and whisk thoroughly into the batter. Scrape the bowl down. Stir in cranberries and pecans. Stir in flour until it just disappears.
Scrape batter into prepared pan and spread smooth. Sprinkle cake with pearl sugar, if using.
Bake for 60 to 70 minutes, rotating once for even color, until a toothpick inserted into the loaf comes out batter-free. Give the cake more time if needed; don’t worry about it getting dark. Cool in pan on a rack until lukewarm, or at room temperature. Serve in slices.
Cake keeps for 5 to 6 days at room temperature. I leave it in the loaf pan, and just cover the cut side with foil. This ensures the sides stay moist the the top stays crisp.