Add all ingredients, except the butter, to a medium saucepan. Cook on low heat until the sauce begins to simmer. Using a whisk, stir gently to melt the sugars and spices together. After about 8-10 minutes at a low simmer, the sauce will thicken.
Turn off the heat. Whisk in the butter a little at the time, slowly melting it while stirring. This will help the butter emulsify into the sauce so it doesn’t separate.
