In a large mixing bowl, whisk together the oat flour, vanilla protein powder, matcha powder, and ground flaxseed until uniform.

In a separate bowl, combine the almond butter, maple syrup, and melted coconut oil, whisking until smooth.

Integrate the wet ingredients into the dry mixture along with the vanilla extract, stirring until a cohesive dough forms.

Line an 8x8 inch square baking pan with parchment paper, allowing for an overhang on two sides.

Transfer the dough into the prepared pan and press firmly into an even layer using a flat-bottomed tool or spatula.

Melt the dark chocolate chips using a double boiler or 30-second microwave intervals, then drizzle over the surface of the bars.

Refrigerate the pan for a minimum of 60 minutes to allow the structure to set.

Lift the bars from the pan using the parchment overhang and slice into 10 equal rectangular portions.