I adapted this from the "California Pot Roast" recipe in The Grassfed Gourmet, by Shannon Hayes. It came out nice and slice-able, with more than enough tasty sauce.
1 3.5 pound (or bigger) roast (I used sirloin tip)
2 tsp. salt
2 tsp. freshly ground pepper
3 tbsp. beef tallow or other fat
2 cups tomatoes, fresh or frozen
1 onion, coarsely chopped
2 cloves garlic, minced
1 tsp. dry mustard
1 tsp. dry basil
1 tsp. dry oregano
1/4 cup apple cider vinegar
Rub the roast with salt and pepper. Brown in a large skillet with the beef tallow, over medium heat--about 3 minutes per side.
Place the vegetables and spices in the slow cooker, and put the browned roast on top. Cover, and cook on low for 5-6 hours (about 7 hours before dinner).
About an hour before dinner, and after those 5-6 hours are up, add the apple cider vinegar. Cook for another hour.
Remove the meat, slice, and place on a warm platter. Meanwhile, simmer the vegetables and sauce in a pot on the stove for a few minutes, and blend with an immersion blender; adjust seasonings. Pour the sauce over the sliced roast, and serve.