Line an 8×8-inch square baking pan with parchment paper with enough overhang on the sides. Set aside.
To make the peanut butter base, place the peanut butter and maple syrup in a large bowl and microwave for 30–60 seconds. Stir until smooth. Add the oat flour and stir again until well combined. Transfer the mixture to the prepared baking pan and press evenly into the pan.
To make the chocolate topping, place the chocolate chips and peanut butter in a small bowl and microwave in 30-second intervals until melted. Stir until smooth. Pour over the peanut butter base and use a spatula to spread evenly. Sprinkle sea salt on top.
Chill in the fridge until completely firm, about 2–3 hours. Cut into 16 slices and serve cold.