Cook broccoli in a large pot of boiling salted water (leave florets attached to stem so it’s easier to get in and out of the pot) over medium-high heat just until crisp-tender, about 2 minutes. Transfer to a paper towel-lined plate. Cook kale (again, leave on the stem to cook it) by dipping into the water just long enough to let the color turn bright green, about 10 seconds. Transfer to plate with broccoli; reserve pot of water. Let vegetables cool, then squeeze out any excess water.