Preheat your oven to 350°F (175°C) and lightly grease an 8-inch round cake pan.

In a large mixing bowl, whisk together the flour, sugar, cocoa powder, baking soda, salt, cinnamon, and cayenne pepper until well combined.

Add the water, vegetable oil, vanilla extract, and vinegar to the dry ingredients.

Whisk the mixture gently until the batter is smooth and no dry lumps remain.

Pour the batter into the prepared cake pan and smooth the top with a spatula.

Bake for 30-35 minutes, or until a toothpick inserted into the center comes out clean.

Allow the cake to cool completely in the pan on a wire rack.

To make the ganache, heat the heavy cream in a small saucepan until it just begins to simmer.

Place the chocolate chips in a heat-proof bowl and pour the hot cream over them; let sit for 2 minutes.

Stir the chocolate mixture until smooth and glossy, then pour over the cooled cake before serving.