Save some berry goodness for the off season
Makes 3 to 4 half-pints, and is best as small batches like this.
Sort fresh berries, discarding any that are soft, moldy or otherwise suspect. Rinse them and drain them well.
Thaw frozen raspberries, saving all their juice.
Stir the berries (including the juice from thawed berries), the sugar and lemon juice together in a bowl, using a rubber spatula
let the mixture stand, stirring gently once or twice, until the sugar has dissolved, about 2 hours (many times I let it sit all day in the refrigerator or overnight).
Wash 4 half-pint jars. Keep hot until needed.
Prepare lids as manufacturer directs.
Scrape the mixture into a large skillet or sauté pan.
Add the butter.
Bring the mixture to a boil, stirring constantly with a straight-ended wooden or nylon spatula, and boil rapidly for 6 minutes. Remove from heat.
The butter helps reduce foam, but if some remains after you’ve removed the skillet from the burner and let the jam settle for about 10 seconds, skim it off. Ladle hot preserves into 1 hot jar at a time, leaving ¼-inch headspace.
Wipe jar rim with a clean, damp cloth.
Attach lid. Fill and close remaining jars.
Process in a boiling-water canner for 10 minutes (at 1,000 to 3,000 ft-process for 15 minutes; 3,000 to 6,000 ft-20 minutes; above 6,000 ft.-for 25 minutes