Prep. Heat oven to 350°F and grease a 9 x 13-inch baking dish. Set aside.
Melt chocolate. Combine 3/4 cup unsalted butter and 4 ounces chopped semi-sweet chocolate in a microwave-safe bowl. If using a microwave, melt the chocolate in 30 second increments, stirring in between, until smooth. If using the stove, place chocolate and butter over medium-low heat and melt, stirring frequently until smooth. Mix in wet ingredients. Add 2 cups granulated sugar, 3 large eggs, 3 tablespoons Cognac or brandy, and 2 teaspoons vanilla extract. Whisk until smooth.
Mix in dry ingredients. Add 1 cup unsweetened cocoa powder, 1 cup all-purpose flour, 1 tablespoon ground cinnamon, and 1/2 teaspoon kosher salt. Fold with a rubber spatula until no dry streaks remain. The batter will be thick and fudgy.
Bake. Bake in the oven until a toothpick inserted in the middle comes out with just a few moist crumbs, about 30 minutes. Remove to a wire rack and let cool 30 minutes or until cool enough to handle.
Roll into balls. Using a fork, scrape the batter into a loose crumb. Take a cookie scoop or a tablespoon and scoop up 1 tablespoon of the crumbs. Pack it tightly with your hands then roll the brownie crumbs into 1-inch sized balls. Place on a baking sheet lined with parchment paper. Try your best not to eat it all at this point. :)
Chill. Chill the balls in the refrigerator for at least an hour and up to a day.