The MIL has requested an 8qt stockpot for Christmas. She has one of those flat cooktops- not induction...I can't think of the name. Radiant top? Anyhow, she can't use just any pot, it has to be perfectly flat so it will rest on the cooktop correctly. Can anyone recommend a brand that will work? Needs to be durable and easy to clean. No non-stick, please. Stainless/hard anodized would be best.