Grind the lentils and quinoa in a coffee or spice grinder, about ½ cup at a time, until a coarse powder forms. Transfer the ground lentils and quinoa to a medium bowl. Add water to cover by about 1 inch. Mix well and soak for one hour.
Drain: Pour the mixture into a fine-mesh strainer over a medium bowl to drain most of the water. Then, hold the strainer under running cold water to rinse the mixture further. Place the strainer back over the bowl to allow the remaining water to drain.
Meanwhile, preheat the oven to 360ºF. Use a nonstick baking sheet or line the sheet with parchment paper or a silicon mat. Lightly grease the baking sheet, mat, or parchment to prevent sticking
Blend: Transfer the ground mixture to the canister of a food processor. Add mustard powder, garlic powder, onion powder, marjoram, baking powder, olive oil, and water. Blend until the ingredients are fully incorporated. Set aside for at least 10 minutes.
Bake: Transfer ⅔ cup batter to the baking sheet. Spread into an even layer, about ¼ to ½-inch thick. Bake for about 12 minutes, or until the batter is firm to the touch and lightly golden. (Bake on the middle or lower rack.)
Notes
Thickness: You can make these flatbreads as thick or thin as you like. Pour the batter onto a greased baking sheet and spread it to your desired shape and thickness. Adjust the baking time accordingly.
Oil: I recommend adding 2 to 3 teaspoons of olive oil to the batter for texture, but this is optional. However, you must lightly grease the nonstick baking tray, silicone mat, or parchment paper or these will stick.
Longevity spices: Add 1 teaspoon long pepper powder, 1-½ teaspoons turmeric, a pinch of black pepper, and 1-½ teaspoons ground black cumin seeds per 1-⅓ cups lentils used.