Slow-Cooker French Dip Sandwiches with Caramelized Onions

To make the caramelized onions, the night before serving, put the onions in a slow cooker, add the butter and 1/2 tsp. salt, and toss to coat evenly. Cover and cook on low for 10 hours, stirring once in the first few hours of cooking if possible. The next morning, stir the onions, re-cover and cook on the high setting until the onions are golden and most of the liquid has evaporated, 1 to 2 hours. If the liquid has not evaporated, set the lid ajar for 1 to 2 hours to evaporate the liquid while the onions continue to cook. (The onions can be caramelized in advance. Let cool to room temperature, then transfer to an airtight container and refrigerate for up to 3 days or freeze for up to 3 months.)

When the onions are ready, stir in the stock, wine and bay leaves.

Season the beef with salt and pepper. In a large, heavy fry pan over medium-high heat, warm the oil. Add the beef and sear, turning as needed, until browned on all sides, about 10 minutes. Transfer the beef to the slow cooker, nestling it in the onion mixture. Cover and cook on low for 4 hours.

Transfer the beef to a cutting board and let stand for a couple of minutes, then snip and remove the strings and cut against the grain into slices about 1/4 inch (6 mm) thick, discarding any large bits of fat. Return the beef to the slow cooker, re-cover and continue to cook on low for 4 hours. The beef should be very tender.

Using a slotted spatula, carefully transfer the beef and onions to a platter. Strain the cooking juices through a fine-mesh sieve into a serving bowl. Transfer any onions captured in the sieve to the platter and discard the bay leaves. Let the cooking juices stand for a few minutes. Using a large spoon, skim the fat from the surface of the juices. Taste the juices and adjust the seasoning with salt and pepper if needed, then keep warm.

To assemble the sandwiches, pile slices of beef and onions onto the bottom half of each roll, dividing them evenly, then top with a slice of provolone. Close with the roll tops and serve, with bowls of the warm cooking juices alongside for dipping. Serves 8.

Adapted from Williams Sonoma Everyday Slow Cooking (Weldon Owen 2018)