Melt the butter in a small saucepan or the microwave and keep it warm.
In a separate small saucepan, whisk together the heavy cream, cornstarch, Dijon mustard, lemon juice, turmeric, black salt and cayenne until smooth with no lumps.
Place over medium low heat and whisk constantly for 2 to 3 minutes until the mixture thickens slightly and coats the back of a spoon. Remove from the heat.
Slowly drizzle in the warm melted butter while whisking vigorously so the sauce becomes silky, thick and glossy.
Season with salt to taste and serve immediately over eggless benedicts, asparagus, salmon or roasted potatoes. If it thickens too much, whisk in a splash of warm water.
