Melt the cocoa butter: Add the cocoa butter to a double boiler or melt it in the microwave.
Wet ingredients: Add the melted cocoa butter, cashew butter, maple syrup, soy milk, vanilla extract, and salt to a mixing bowl. Stir until well combined.
Almonds & chocolate: Roughly chop the almonds and chocolate with a knife.
Dry ingredients: Add the almonds, chocolate, buckwheat groats, and oat flour to the mixing bowl. Stir until evenly combined.
Press: Line an 8x8" (20x20 cm) square baking pan (or a container of a similar size) with parchment paper. Tightly press the oat bar mixture into the pan and smooth out the surface.
Topping: Melt the dark chocolate. Drizzle it on top of the oat bar mixture and sprinkle with coarse sea salt. Freeze for 10 minutes until solid.
Slice: Remove the oat bar mixture from the baking pan and cut it into 12 equal bars. Store them in an airtight container in the refrigerator for up to 1 week.