Heat heavy cream in a small saucepan over high heat until simmering.

Finely chop bittersweet chocolate and place in a medium bowl.

Pour the hot cream over the chocolate and let sit for 2 minutes to melt the chocolate.

Stir the mixture until smooth and fully combined.

Stir in the cognac, if desired, for added flavor.

Allow the mixture to cool completely at room temperature.

Cover the bowl with plastic wrap, pressing it onto the surface to prevent skin formation.

Refrigerate for about 4 hours, or until the mixture is firm enough to handle.

Pour cocoa powder into a shallow dish.

Use a teaspoon or small scoop to form the truffle mixture into 1-inch balls.

Roll each ball in the cocoa powder, ensuring even coating.

Place the coated truffles in small muffin tins or on a plate.

Refrigerate the truffles until ready to serve to maintain firmness.