Slow-Cooker Vegetarian Ragout Over Couscous

Put onions, carrots, celery, butter and oil in a heavy-bottomed Dutch oven and place over medium-high heat. Cook, stirring occasionally, until the vegetables are lightly browned, 8 to 15 minutes.

Add ground beef and break it up with a wooden spoon. Season with salt and continue stirring until the meat has lost its red color, about 4 minutes.

Add wine and cook, stirring occasionally, until it has almost completely evaporated, 18 to 25 minutes. Add milk and nutmeg and cook, stirring occasionally, until the milk has mostly evaporated, 12 to 18 minutes.

Coarsely chop tomatoes and add them and their juice to the pot. Once the tomatoes have started bubbling, reduce the heat to low so that the sauce is barely simmering. Cook uncovered for 4 hours, stirring occasionally. If all the liquid evaporates before the cooking time is up, add water 1/2 cup at a time as needed. After 4 hours, make sure all the liquid has evaporated before you remove the sauce from the heat. Blot or skim any fat from the surface before serving.