1. In a medium heatproof bowl, whisk egg yolks and 1/2 cup sugar until pale yellow and thick, about 2 minutes. In a medium saucepan, bring milk and salt to a bare simmer. Whisking constantly, slowly pour hot milk mixture into yolk mixture.

2. Pour yolk mixture back into saucepan. Add peppercorns, cardamom, allspice, clove, ginger, and orange zest. Cook over medium heat, stirring constantly with a wooden spoon, until mixture is just thick enough to coat back of spoon and hold a line drawn by your finger, 3 to 5 minutes.

3. Pour mixture through a fine-mesh sieve into a large bowl; discard solids. Let cool, stirring occasionally, about 20 minutes. Add cream, bourbon, rum, and cognac; cover and refrigerate overnight.

4. Whisk remaining 1/4 cup sugar and egg whites in a heatproof mixer bowl set over (not in) a pan of simmering water. Whisk until sugar is dissolved and mixture is warm (it should feel smooth between your fingers), 2 to 3 minutes. (For fully cooked eggs, a thermometer inserted into meringue should register 160 degrees.) Remove from heat. With a mixer on high speed, beat until stiff peaks form, about 5 minutes. Fold into eggnog.

5. Pour into glasses (or a punch bowl); top with a dollop of whipped cream and sprinkle with orange zest.