Dulce de leche ice cream, shaved chocolate, toasted almonds and/or dulce de leche, for topping
Preheat the oven to 325 degrees F. Line an 8-inch-square baking dish with foil, leaving a 2-inch overhang on 2 sides; coat with cooking spray.
Melt the butter and semisweet and unsweetened chocolate in a medium saucepan over medium heat, stirring, until smooth. Remove from the heat and whisk in the brown sugar and granulated sugar until combined. Whisk in the eggs, vanilla and almond extract. Add the flour, 1/2 teaspoon cinnamon and the salt and stir until the batter looks like hot fudge.
Pour the batter into the prepared baking dish and spread in an even layer. Bake until a toothpick inserted into the center comes out with moist crumbs, 30 to 35 minutes. Transfer to a rack and let cool completely in the pan.
Beat the heavy cream, cayenne and a pinch of cinnamon in a large bowl with a mixer on medium-high speed until soft peaks form, about 2 minutes. Lift the brownies out of the pan using the foil and cut into pieces. Serve topped with ice cream, the spiced whipped cream, shaved chocolate, almonds and/or dulce de leche.