How to Make It
Preheat the oven to 350˚F.
Lightly butter the bottom and sides of a 10-inch springform pan. Dust bottom and sides with the cocoa, shaking to remove excess.
Combine the bittersweet chocolate and butter in a large bowl. Microwave for 1 minute or until completely melted and smooth, stirring at 30-second intervals. (Alternately, melt in a small metal bowl set over a saucepan of simmering water, stirring until smooth.) Let cool slightly. Whisk in the sugar and cinnamon, if desired. Whisk in the eggs, 1 at a time, whisking well after each addition. Sift the remaining 1 cup cocoa over the mixture, and whisk until just combined.
Pour the batter into the prepared pan, and bake 30 to 35 minutes or just until barely set. Transfer to a wire rack; let cool for 10 minutes. Run a knife around the edges to loosen, and remove sides. Remove to a serving platter, and let cool completely. Dust with additional cocoa or powdered sugar. Serve with ice cream or sweetened whipped cream, if desired.
Excerpted from Martina’s Kitchen Mix by Martina McBride. Copyright © 2018 Oxmoor House. Reprinted with permission from Time Inc. Books, a division of Meredith Corporation. New York, NY. All rights reserved.