Heat the oven to 350°F. Grease an 8- or 9-inch tube pan and dust it with cocoa powder.
In a large bowl, whisk together the flour, chile, baking soda, and salt; set aside. Combine the butter and stout in a small bowl and heat it over a double boiler until the butter is melted. Add the sugar and cocoa powder to the butter mixture and stir to combine.
In a small bowl, whisk together the eggs, espresso powder, and vanilla. Stir in the sour cream, then add the mixture to the butter mixture. Fold in the flour mixture until just combined, then gently stir in the chocolate chunks.
Pour the batter into the prepared pan. Bake until a toothpick inserted into the center of the cake comes out with a few moist crumbs, 40 to 45 minutes. You will also see a few oozy chocolate spots. Remove the cake from the oven and let it cool completely. Run a knife between the cake and the pan and then invert the cake onto a rack. Store at room temperature, covered with plastic wrap, for up to a week or wrap in plastic wrap and foil and store in the freezer for up to a few months.