In a small saucepan over medium-low heat add the milk and cream or non-dairy milks, the vanilla bean seeds and a pinch of sea salt. Add your sweetener now, if you are using.Whisk well to combine and continue to whisk as it heats. Bring to a barely bubbling simmer, turn the heat down to low and let it infuse for 5 minutes. Remove from the heat and add the gelatin, if using. Whisk really well to incorporate and remove any lumps. Let cool.Pour into a glass serving container or mason jar, cover tightly and place into the fridge, it will thicken as it cools. Keeps up to a week.