Get your double cream and whole milk poured into a saucepan. Cut your vanilla pod in half, scraping the seeds into the saucepan and add the exterior pod as well. Give it a wee whisk and place over a medium heat. Bring it up to the point were it just starts to simmer, gently stirring every so often. Just as it starts to simmer and steam, knock off the heat and place your lid on. Allow that to sit for at least 30 minutes to gently cool and infuse.