Preheat your oven to 350°F (175°C). Grease and flour a 9×5 inch loaf pan.

In a large bowl, mix together the pumpkin puree, granulated sugar, brown sugar, and vegetable oil until fully combined. Add the eggs, one at a time, beating well after each addition.

In another bowl, whisk together the flour, baking soda, baking powder, cinnamon, nutmeg, and salt.

Gradually pour the dry ingredients into the wet mixture, stirring until just combined. Be careful not to over-mix; a few lumps are perfectly fine.

Gently fold in the chopped walnuts or pecans if using.

Pour the batter into the prepared loaf pan and smooth the top with a spatula.

Bake in the preheated oven for about 60 minutes, or until a toothpick inserted into the center comes out clean.

Let the bread cool in the pan for about 10 minutes, then transfer it to a wire rack to cool completely.