In the bowl of a food processor, process the rolled oats to a fine flour.
Combine processed oats, cocoa powder, ground chaga, baking soda and salt in a separate bowl and set aside.
Process melted butter and chopped, pitted dates in a food processor until the mixture is thick and pasty.
Scrape date/butter mixture from the bowl into another bowl.
Add a egg and vanilla and stir until combined.
Add the dry ingredients to the wet and stir until thoroughly combined.
The batter will be very thick and shiny.
Spread batter into a greased 8x8 pan.
Bake at 350 degrees F for 12-15 minutes, until a skewer inserted in the center reveals moist crumbs.
Allow to cool and cut into squares.