In a separate bowl, mix together with a whisk the all-purpose flour, rolled oats, salt, Brewer's yeast, flax meal, baking soda, baking powder, and cinnamon (if using). This is important to make sure your ingredients are evenly distributed.
2 cups (275g) all-purpose flour, 2 cups (180g) old-fashioned rolled oats, 1 teaspoon (6g) fine sea salt, 3 Tablespoons (30g) Brewer's yeast, 2 Tablespoons (14g) ground flax meal, 1 teaspoon (5g) baking soda, 1 teaspoon (4g) baking powder, 1 1/2 teaspoons (4g) ground cinnamon