Preheat oven to 350 degrees F.Line an 8 x 8 inch baking pan with parchment or spray/grease with coconut oil.In a large bowl add the oat flour, rolled oats, sea salt and ground flax.Top with peanut butter and maple syrup.The batter should be slightly sticky, but not wet. Add water as needed to get to right consistency (see video for tips!).Add in chocolate chips, if using.Spread out batter in baking pan using wet hands. Pack in tightly and ensure top is flat.Bake for 18-20 mins or until edges are slightly brown.Let sit for 20 minutes before removing from pan and cutting in 12 bars.Store in an airtight container for up to 4 days on countertop or freeze for several months.