Preheat the oven to 350 degrees.
Mix the dry ingredients together (flour, sugar, salt, and baking powder).
Mix the wet ingredients into the dry, adding water only as needed. The batter should be moist, but not sticky.
Let the dough sit for a few minutes to allow the oats to absorb some of the moisture.
Mix the sugar and cinnamon together on a plate.
Pinch off pieces of dough (10 total) and form each piece into a ball.
Roll each ball in the cinnamon/sugar mix until lightly coated on all sides.
Press down on each ball to form a cookie shape.
Place all of the coated cookies onto a parchment paper-lined baking sheet.
Bake for 10 minutes.
Let cool for five minutes on the baking sheet.