"Rhubarb, cinnamon, and nuts create the perfect combination in this delightful, spring-worthy bread. It keeps up to 3 days, wrapped and at room temperature, or frozen up to 3 months in a zip-top plastic bag."
Preheat oven to 350 degrees F (175 degrees C). Grease and flour the bottom and 1/2 inch up the sides of a 9x5-inch loaf pan.
Stir together 1/3 cup sugar, pecans, and cinnamon in a small bowl.
Stir together flour, baking powder, salt, and remaining 1 cup sugar in a large bowl. In another bowl, beat egg with a fork; stir in milk and oil. Add egg mixture to flour mixture. Stir until just moistened; batter should be lumpy. Fold in rhubarb.
Spoon 1/2 of the batter into prepared pan, then sprinkle with 1/2 of the cinnamon mixture. Repeat with remaining batter and cinnamon mixture. Using a table knife or thin metal spatula, cut down through batter and pull up in a circular motion to marble the cinnamon mixture.
Bake until a toothpick inserted in center comes out clean, 55 to 60 minutes. Transfer pan to a wire rack and let cool 10 minutes. Remove bread and let cool completely on rack, at least 30 minutes.
Wrap bread with plastic wrap and let stand at room temperature, 8 hours to overnight, before slicing. You don't have to wait overnight, but the bread is much easier to slice and has a better texture if you do.