Prep the oven: Arrange a rack in the bottom of the oven and another one in the middle. Fill a metal roasting pan or baking pan with water and place on the bottom rack. Heat oven to 350°F and let water heat as oven heats.
Prep the pan: Grease a 8-inch round cake pan and line the bottom with parchment paper. Grease the parchment paper.
Melt chocolate: Fill a small saucepan halfway with water and bring to a boil over medium-high heat. Reduce heat to just barely a simmer. Combine chocolate, 1/2 cup olive oil, and 2/3 cup sugar in a large heatproof glass or metal bowl and set the bowl over the simmering water. Stir frequently until the chocolate is completely melted and mixture is smooth.
Finish batter: Remove from heat and whisk in the teaspoon cinnamon, 1/2 teaspoon almond extract, 4 eggs, 1/4 cup cocoa powder, and 1/2 teaspoon salt.
Pour batter into cake pan.
Bake: Place cake pan on middle rack above the pan of water and quickly close the door to trap the steam. Bake until the edges are set and a toothpick comes out with a few moist crumbs, about 30-40 minutes.
Make the cinnamon whipped cream: While the cake is baking, combine 1 cup cold heavy cream, 3 tablespoons powdered sugar, and 1 teaspoon cinnamon in the bowl of a stand mixer fitted with a whisk attachment and whip to soft, fluffy medium peaks. Chill until ready to serve.
Let cool: Set cake on a wire rack to cool for 10 minutes then invert on top a serving platter or cake stand.
Serve! Serve warm or room temperature with cinnamon whipped cream, a dusting of powdered sugar, and toasted almonds.