Whisk flour, baking powder, cinnamon and salt together in a large bowl. Combine non-dairy milk with maple and sugar, if using. Pour wet mixture into the dry mixture and stir until just combined; a few lumps are okay. Let rest 10 minutes. Meanwhile, heat a skillet over very low heat. Transfer mixture to a large glass/liquid measuring cup or use ¼-cup measuring cup. Pour ¼ cup batter into a non-stick skillet. Cook on one side until bubbles form, gently flip, and cook for another 2-3 minutes.