Whisk the egg yolks, maple syrup, and honey together in a large bowl until smooth and slightly lightened in color. Set aside
Combine the milk, cream, nutmeg, cinnamon, allspice, cloves, and salt in a heavy-bottomed pot. If using a vanilla bean, add it here. Heat over medium-low, stirring occasionally, until the mixture is steaming and reaches about 160°F. Do not allow it to boil.
Temper the egg yolks by slowly ladling about 1/2 cup of the warm dairy mixture into the yolk bowl, whisking constantly. Add more warm dairy mixture to the egg mixture, whisking continuously. This gradual process prevents the eggs from scrambling. Add a total of 2 to 3 cups of dairy to the egg. The egg bowl should begin to feel warm to the touch.
Pour the tempered yolk mixture back into the pot with the remaining dairy. Cook over medium-low heat, stirring constantly with a wooden spoon or silicone spatula, until the mixture reaches 170°F and coats the back of a spoon. This takes about 5–8 minutes. Do not let it boil.
Remove from heat and pour immediately through a fine-mesh sieve into a clean container.
Stir in the vanilla extract if using.
Allow to cool slightly, then cover and refrigerate until thoroughly chilled, at least 4 hours. Overnight is ideal—the flavors meld beautifully.
Serve cold with freshly grated nutmeg on top. This eggnog is also delightful when served warm for a relaxing evening drink. For a boozy version, add 1/2 oz bourbon and 1/2 oz amaretto per 8-ounce serving.