If you don't keep buttermilk around, use this substitution: for 1 cup buttermilk, use 1 cup milk + 1 tsp vinegar or lemon juice. Allow the milk/vinegar solution to sit for 5 minutes, then use just like buttermilk in your recipe.
The syrup will expand a LOT while cooking. Use a very large saucepan to avoid spill overs.
This recipe halves well. I usually only make half for my family.