In a stand mixer fitted with a whisk attachment or in a large bowl with a hand mixer or using a whisk, beat the heavy cream just until stiff peaks form.
Transfer to a piping bag fitted with a large star tip and place in the refrigerator while you prepare the drink.
Divide the brandy between two small heat-safe glasses, 2 tablespoons (30 milliliters) each.
Pour the egg liqueur into a small saucepan and place over medium low heat.
Cook, whisking constantly, especially the bottom and sides, just until hot, but not boiling. Do not over-cook.
Pour the heated egg liqueur equally between the two glasses over the brandy.
Stir with a spoon to combine the egg liqueur and brandy.
Pipe a generous amount of whipped cream in each glass.
Serve immediately with a dusting of ground cinnamon.