Pour the cream, half-and-half, sugar, and salt into a medium sauce pot. Place the pot over medium heat until it comes to a low simmer.
If using a vanilla bean, cut the bean down the center lengthwise. Carefully open the bean and scrape out the paste. Add the buds and vanilla paste to the cream mixture. Stir; then remove from heat and cover. *Add a drop or two of food coloring if you want to enhance the lavender color.
Place the covered pot in the refrigerator for at least 4 hours to cool. (If you’re in a hurry, place it an airtight container and put in the freezer for 1 hour until thoroughly chilled, but NOT frozen!)
Once the mixture is chilled, strain out the lavender buds and pour into an ice cream maker. Churn for 20+ minutes until the desired consistency is reached.
Meanwhile, chop the chocolate bar into fine shards. Add the chocolate to the ice cream maker. Churn until the chocolate is evenly distributed. Serve immediately or put in an airtight container and freeze.