A dish straight off the menu of chef Clare de Boer's New York restaurant, King, this kale purée is a deep green smooth spread made with plenty of Tuscan olive oil and a lovely side to balance out heavier holiday dishes.
Place garlic in a large pot of water and bring to a boil; generously season with kosher salt. Add kale and cook until very tender, 10 to 12 minutes. Reserve 1 cup cooking water, then drain kale and garlic. When cool enough to handle, squeeze as much water from kale as possible.
Transfer kale and garlic to a food processor with 1 teaspoon flaky salt; pulse into a paste. With motor running, slowly add oil. Add reserved water, a little at a time, until purée is thinned to desired consistency. Serve warm or room temperature.
This kale purée can be made up to two days ahead and refrigerated in an airtight container. Bring it to room temperature or gently rewarm before serving, and loosen with a bit of water, if needed.