just to check - peel spuds, chop, wash well under running water, dry well, fry at 130 degrees for 7 minutes, remove, allow to cool, reheat fat to 190, fry for 5 minutes or so to brown, k?

After this, you might consider grating some (quite a lot) parmesan on top and grilling them to melt the cheese, before anointing with some good quality truffle oil.

You won't need ketchup.