Place the oven rack in the center position of the oven, and preheat the oven to 350 degrees F. Spray an 8x8-inch baking dish with nonstick spray. Line with parchment paper, leaving some hanging out opposite sides like handles.
In a large heatproof bowl set over a pan of simmering water melt together the chopped chocolate and cannabis butter. When the chocolate is almost melted, remove from the heat and stir until the mixture is completely melted together and smooth. Let cool 5 minutes.
In a separate bowl, sift together the whole wheat pastry flour, all-purpose flour, cocoa powder, and salt.
Once the chocolate mixture has cooled, whisk in the granulated sugar until combined. At this point, the mixture will look grainy. Stir in the eggs, one at a time, fulling combining between each addition. Keep stirring until chocolate mixture is smooth and glossy. Stir in the vanilla extract.
Add the dry ingredients to the chocolate mixture a little at a time,stirring in between each addition, just until the flour disappears. Slowly stir in the beer. Fold in the chocolate chips.
Scape the batter into the prepared pan and smooth the top. Place in the oven and bake 30 minutes. Cool to room temperature, then remove from the pan.
Meanwhile, prepare the Guinness frosting: Beat the cannabis butter until light and fluffy. With the mixer running on low, slowly beat in the powdered sugar. Add the vanilla extract and 2 tablespoons of stout. Spead over top of your cooled brownies & enjoy!