Directions

1. Remove ribs and stems from 1 bunch Swiss chard (about 8 oz.) and thinly slice. Tear leaves into bite-size pieces. Transfer to a large heatproof bowl; add 1 bunch curly kale (about 7 oz.), ribs and stems removed, leaves torn, 1 bunch watercress (about 7 oz.), tough stems trimmed, and 8 spring onions or 12 scallions, thinly sliced, and toss to combine.
2. Cook bacon , cut into 1" pieces, in a medium skillet over medium heat, stirring often, until browned and mostly crisp, 6–8 minutes. Using a slotted spoon, transfer bacon to a small plate. Carefully pour fat into a heatproof measuring cup (you should have ¾ cup; make up the difference with vegetable oil if needed). Return fat to skillet; heat over medium until just beginning to smoke, 6–8 minutes.
3. Meanwhile, add ¾ cup apple cider vinegar, 2 tsp. freshly ground pepper, 1½ tsp. flaky sea salt, and half of cooked bacon to bowl with greens and toss to combine.
4. Carefully pour fat over salad (it will sizzle dramatically so stand back slightly to avoid any splatter); toss with tongs to coat. Top with remaining bacon.