Preheat the oven to 350°F. Line a loaf pan with parchment paper and set aside.
In a large bowl, mix together the flour, baking powder, baking soda, pumpkin pie spice, stevia and brown sugar until combined.
In a medium bowl, beat the eggs. Mix in the protein shake and oil until smooth.
Slowly mix in wet ingredients into the dry ingredients until just combined. Do not overmix.
Pour the batter into the prepared loaf pan and sprinkle with pumpkin seeds. Bake in the preheated oven for 45-55 minutes, or until a toothpick inserted into the centre comes out clean.
Allow to cool in the pan for around 15 minutes before transferring to wire racks to cool completely.