Bread-and-Butter Pickles

From the garden

• 3 lb pickling cucumbers, cut into ¼-inch rounds
• 2 medium yellow or white onions, halved and thinly sliced

From the pantry

• ¼ cup canning or pickling salt · for the ice-brine stage; most of it drains away
• 2½ cups sugar
• 2½ cups distilled white vinegar (5%) · the tested sugar-vinegar syrup: don't cut the vinegar
• 1½ tbsp mustard seed · celery seed (1 tsp) and ground turmeric (2 tsp) are the other classic additions if you keep them

1. Toss the cucumber and onion slices with the canning salt in a large bowl, bury a tray of ice cubes in the mix, and let stand 1½ hours. This draws out water so the pickles stay snappy instead of going limp in the sweet brine.
2. Meanwhile, wash 4 pint jars and keep them hot in the water-bath canner as it heats; wash the lids and bands.
3. Drain the vegetables, rinse well under cold running water, and drain again thoroughly.
4. Bring the sugar, vinegar, and mustard seed to a boil in a wide pot, stirring to dissolve the sugar. Add the drained vegetables and return just to a boil. Don't let them simmer soft.
5. Pack the hot vegetables and syrup into the hot jars leaving ½ inch headspace, release air bubbles with a thin spatula, wipe the rims, and screw the bands on fingertip-tight. Process in boiling water covering the jars by 1 inch for 10 minutes; at 1,001–6,000 ft process 15 minutes, above 6,000 ft 20 minutes.
6. Cool the jars undisturbed on a towel for 12–24 hours, check that the lids don't flex, and refrigerate any that didn't seal. Best after 4 weeks in the jar.