Preheat your oven to 350°F (175°C). Grease or line a loaf pan.
In a large bowl, mix pumpkin puree, eggs, sugar, orange juice, orange zest, vanilla, and oil until smooth.
In another bowl, combine gluten-free flour, baking powder, cinnamon, and salt.
Slowly add dry ingredients to wet ingredients, mixing gently until just combined.
Fold in walnuts, raisins, or chocolate chips if using.
Pour batter into the loaf pan and smooth the top.
Bake for 45-55 minutes or until a toothpick inserted in the center comes out mostly clean
Let bread cool completely, then wrap tightly before storing