Save space in your oven and use your slow cooker to whip up this easy, classic stuffing. Hearty whole-grain bread gets toasted in the oven for only 10 minutes (and you can toast the cubes ahead of time!) while your slow cooker does the rest.
Preheat oven to 375 degrees F. Place bread cubes in a single layer on a large rimmed baking sheet; bake until lightly toasted, about 10 minutes. Remove and cool completely, about 20 minutes.
Melt butter with oil in a large skillet over medium-high heat; add onion and celery and cook, stirring often, until tender, 6 to 8 minutes. Place the cooled bread cubes in a large bowl; stir in the onion mixture, broth, eggs, sage, thyme, salt and pepper. Lightly coat a 5- to 6-quart slow cooker with cooking spray. Transfer the bread mixture to the slow cooker.
Cover and cook on High for 30 minutes; reduce heat to Low and cook until cooked through and a knife inserted in center comes out clean, 3 to 4 hours.
To make ahead: Toast bread (Step 1); store toasted bread cubes in an airtight container at room temperature for up to 3 days. The stuffing may be held, covered, on Warm for up to 2 hours.
Equipment: 5- to 6-quart slow cooker