Combine cream, buttermilk, and lavender in a glass jar; cover with a tight-fitting lid. Let stand at room temperature (approximately 70º) until thickened, 8 to 24 hours. Stir well and refrigerate. Use within 10 days. Use remaining crème fraîche for additional recipes, if desired.
Notes
Note: Crème fraîche can be spooned over fresh fruit, puddings, and warm cobblers, and also used as a thickener for desserts and sauces.
Recipe by Victoria at https://victoriamag.com/lavender-creme-fraiche-cupcakes-recipe/