In a bowl or jar, combine the chia seeds, eggnog, cinnamon, nutmeg, and vanilla extract. Stir or whisk thoroughly to ensure the chia seeds are evenly distributed and no clumps form.

Cover the mixture and place it in the refrigerator for at least 2 hours, or leave it overnight to allow the chia seeds to fully absorb the liquid and create a thick, pudding-like texture.

After chilling, mix in the Greek yogurt or coconut cream for added richness, if desired.

Serve with a dollop of whipped cream, a sprinkle of cinnamon or nutmeg, and garnish with sugared cranberries and rosemary for a festive touch.