Preheat oven to 250 degrees F.
Pour pecans into a 9 x 13 baking dish and place on center rack in oven. Roast, stirring occasionally, until they turn a deep brown color. (Don’t let them overcook as they will darken as they cool). This takes about an hour.
Remove pecans from oven and stir in pieces of butter. Stir until butter melts, and return to oven if needed to get butter to melt.
Add salt to taste while pecans are still hot. Serve still slightly warm for best flavor, or let cool and package in an airtight tin to store.
Packaging tip: Don’t gild the lily is a good rule of thumb here. Place pecans in your best tin for safe-keeping. Or, if you know the pecans will be gobbled up at once, tuck into a pretty glass bowl, add a ribbon and you’re set.