"This creamy onion gravy gets its sour tang from buttermilk. Use with mashed potatoes, or as we had them when I was a child, German dumplings. Leftover cooking water from potatoes is best, but regular water will do."
1Heat vegetable oil in a medium saucepan over medium heat, and stir in the onion. Cook onion until tender, then set aside. Stir flour into the saucepan. Slowly cook and stir in the remaining oil 15 minutes, or until golden brown.
2Whisk the buttermilk into the flour mixture. Blend in the water, adjusting the amount as necessary to attain desired consistency. Season with salt and pepper. Serve with the reserved onions.