Preheat the oven to 350°F (175°C) and grease a 9×5-inch loaf pan.

In a large bowl, mix flour, sugar, baking powder, baking soda, and salt.

In another bowl, combine the beaten egg, orange juice, oil, and zest.

Add wet ingredients to dry, mixing until just combined. Fold in cranberries and walnuts.

Pour batter into the loaf pan, spreading evenly.

For the crumble, combine brown sugar, flour, butter, and cinnamon until crumbly.

Sprinkle crumble over the batter.

Bake for 50-60 minutes, or until a toothpick comes out clean.

Cool in the pan for 10 minutes, then move to a wire rack