Line a non-stick cake pan (18 x 26 cm) with parchment paper.
Once soaked, rinse quinoa well and let it drain. Place quinoa into a food processor or a blender, along with almonds, flaxseeds, lemon juice, garlic (optional), water, baking powder, and salt, and blend until all is well combined and the batter is relatively smooth.
Pour the batter into the prepared pan and sprinkle with seeds (pumpkin, sunflower, cumin seeds).
Bake for approx. 40 minutes or until lightly golden.
Remove from the oven and allow to cool for a bit before removing it from the pan.
Gently peel the parchment paper off the flatbread.