To infuse cream or milk, combine the dairy and the flavor ingredient in a pan and bring the milk up to a simmer. As soon as you see bubbles start to foam on the top, turn off the heat and let the cream sit until it's cooled to room temperature. Then strain out the solids and continue proceed with using the cream in your recipe.
If the flavor isn't as strong as you like, you can re-heat the milk and infuse it again with fresh ingredients. As long as you don't let it boil too long or scorch, dairy can be reheated a few times before it starts getting that cooked flavor.
Almost anything can be used to infuse milk! Any herb or spice, fresh or dried, works very well. Use the whole spice whenever possible, like whole cinnamon sticks, whole cardamom pods, or whole star anise. You can also infuse coffee beans or any kind of tea in your cupboard, ginger, vanilla beans, lemongrass - heck, even chili peppers, if you wanted!
Give it a try!
(Image: Faith Durand)