Bring milk to a simmer in a small saucepan over medium-low heat. Whisk in cinnamon, turmeric, ashwagandha, cardamom, ginger, if using, and nutmeg; season with pepper. Whisk vigorously to incorporate any clumps. Add coconut oil, reduce heat to low, and continue to cook until warmed through, 5–10 minutes (the longer you go, the stronger the medicine). Remove from heat and let cool slightly. Stir in honey (you want to avoid cooking honey or you'll destroy its healing goodness). Pour into a mug, drink warm, and climb right into bed.