Wash glass jars and lids with hot water or run through the dishwasher. Dry thoroughly. (You'll end up with about 5 cups of marmalade, so the number of jars you'll need will depend on what size they are.)

Place the raspberries in a medium-size bowl and crush them with the back of a spoon or a potato masher.

Remove colored zest (just the colored part, not the white pith) from the lemons and oranges, using a small zester (see note in post above).Transfer the zest to the bowl with the raspberries.

Cut the remaining peel off of the lemons and oranges and coarsely chop the fruit into small pieces, discarding any seeds and the white core and reserving any juice. Transfer the fruit and juice to the bowl with the raspberries and zest. Stir to combine.

Transfer exactly 2 cups of the fruit mixture to a large pot. If you don’t have quite enough, add a bit of water or orange juice to make exactly 2 cups. If you have extra, discard (or use for something else) any remaining fruit mixture.

Add the sugar and butter to the pot and stir until well mixed. Turn the heat to medium-high and stir frequently until the mixture comes to a full rolling boil (a boil that you can’t stir down). Set a timer for 30 seconds and boil, stirring continuously. After 30 seconds, remove from heat.

Transfer marmalade to prepared containers immediately and fill to within ½ inch of tops. Wipe off top edges of containers and immediately cover with lids. Let stand at room temperature for 20-24 hours to complete the setting.

Store in refrigerator up to 3 weeks or freeze extra containers up to 1 year. Thaw in the refrigerator before using it.