Make the brownies: Preheat the oven to 325 degrees F. Butter a 10-inch ovenproof skillet; set aside. Combine the butter and chocolate in a medium saucepan over medium heat. Cook, stirring occasionally, until melted and smooth, 3 to 5 minutes. Whisk in the brown sugar and granulated sugar until incorporated. Set aside to cool slightly, then whisk in the eggs and vanilla. Whisk in the flour, chile powder, cinnamon, salt, orange zest and cloves until smooth. Pour the batter into the prepared skillet and bake until a toothpick inserted into the center comes out clean, 35 minutes. Let cool slightly.
Meanwhile, make the chocolate sauce: Combine the heavy cream, butter, brown sugar, corn syrup and salt in a medium saucepan. Cook, whisking, until melted and barely simmering, 3 to 4 minutes. Whisk in the chocolate, cocoa powder, espresso powder and cayenne until smooth and slightly thickened. Let cool slightly.
Cut the brownies into wedges. Top with ice cream and the chocolate sauce.
You can make the brownies in a 9-inch square pan instead; the baking time is the same.