Preheat oven to 400 degrees F. Tear off a piece of foil twice as large as crust. Fold it in half and smear it with butter; lay buttered side onto crust
. Weight foil with a pile of dried beans
(these can be reused for this purpose), pie weights
, or a tight-fitting ovenproof skillet or saucepan
- anything that will sit flat on the surface. Bake 12 minutes, then remove foil and continue to bake at 350 degrees F, until crust is a beautiful shade of brown, another few minutes. Remove and let cool on a rack while you prepare filling.
in a heavy 6-inch or 8-inch saucepan or deep skillet with a tablespoon of water and turn heat to medium. Cook, gently shaking pan occasionally, until sugar melts; then cook, stirring occasionally and scraping sides with a heat-proof flexible spatula
, until mixture turns golden.
Turn heat to low, then carefully add butter and cream
. Cook, stirring constantly, until butter
melts and mixture is uniform. Stir in walnuts and a large pinch of salt if you like, then spread on crust. Refrigerate for about an hour, then sprinkle with a little more salt and serve.