This is a 3-pound sirloin tip roast slow-cooked on low for 8 hours with Montreal steak seasoning and a mix of carrots, broccoli, cauliflower, asparagus, mushrooms, and red onion. The honest reason to make it: one pot, no searing, no sauce-making, and dinner is ready when you walk back in the door.
The short version of why this works
Two things make this recipe succeed. First, Montreal steak seasoning does a lot of work on its own — it has salt, pepper, garlic, and coriander already balanced, so you get a well-seasoned roast without measuring out five separate spices. Second, the vegetables go in at different times. Carrots and red onion are sturdy enough to cook the full 8 hours alongside the beef. Broccoli, cauliflower, asparagus, and mushrooms go in halfway through — around the 4-hour mark — so they cook through without turning soft and waterlogged. That staggered timing is the only real technique here, and it’s the difference between a good result and a disappointing one.
Common problems and fixes
- Roast comes out tough instead of tender: This almost always means it didn’t cook long enough, or it cooked on high the whole time. Sirloin tip is a lean cut that needs low, slow heat to break down properly. Stick to low for 8 hours. High heat for 4 hours is possible but produces a firmer, less forgiving result.
- Too much liquid pooling at the bottom: The vegetables release a lot of moisture as they cook. If you end up with more liquid than you want, remove the lid for the last 20–30 minutes. Don’t add water or broth — the beef and vegetables create their own.
- Asparagus turns mushy: Six to eight spears cut into 2-inch pieces need no more than 3.5 to 4 hours in the slow cooker. If anything, err on the side of adding them a little later than the other delicate vegetables rather than earlier.
- Seasoning tastes flat after 8 hours: A light sprinkle of flaky salt over the sliced beef just before serving brings the flavors back into focus. Skip the garnish herbs — not worth the extra dish.
- Roast is hard to slice cleanly: Let it rest in the slow cooker with the lid off for 10 minutes after you turn it off. It firms up just enough to slice without falling apart entirely, which makes portioning much easier.
Storage and reheating
Leftovers keep well in an airtight container in the fridge for up to 4 days. Store the beef and vegetables together with any cooking juices — the liquid keeps the meat from drying out. To reheat, add a portion to a small saucepan with a splash of the cooking liquid and warm over medium-low heat until just heated through, about 5 minutes. Microwaving works too; cover the container loosely and use 50% power in 90-second intervals to avoid toughening the beef. For freezing, portion the beef and vegetables into freezer-safe containers with some of the juices and freeze for up to 3 months. Thaw overnight in the fridge before reheating.
Paleo Roast Beef
Ingredients
- 1 small red onion peeled and quartered
- 1 cup baby carrots
- 1 small bunch asparagus about 6–8 spears, tough ends trimmed, cut into 2-inch pieces
- ½ cup mushrooms cremini or button, halved
- ½ cup broccoli florets
- ½ cup cauliflower florets
- 1 tablespoon Montreal Steak seasoning
- 3 lbs sirloin tip roast approximately
Instructions
- Pat the sirloin tip roast dry with paper towels. Rub the Montreal steak seasoning evenly over all sides of the roast.
- Place the seasoned roast in the slow cooker. Add the baby carrots and quartered red onion around the beef. Cover and cook on low heat for 4 hours.
- After 4 hours, add the broccoli, cauliflower, asparagus, and mushrooms around the roast. Cover and cook on low for an additional 3–4 hours, until the beef reaches an internal temperature of 195–205°F / 90–96°C for well-done pull-apart texture, or 145°F / 63°C for medium-rare.
- Remove the roast from the slow cooker and let it rest on a cutting board, loosely tented with foil, for 10–15 minutes before slicing against the grain.
- Serve the sliced roast beef with the slow-cooked vegetables and spoon the cooking juices over the top.
Notes
Nutrition
Frequently asked questions
Can I use a different cut of beef?
Chuck roast is the most reliable substitute and is widely available. It has more fat marbling than sirloin tip, so it turns out slightly richer and even more tender after 8 hours on low. Bottom round works too but can be a little drier — keep an eye on it toward the end.
Do I need to add any liquid to the slow cooker?
No. The beef releases moisture as it cooks, and the vegetables add to that. Starting with no added liquid is intentional — it keeps the seasoning concentrated rather than diluted into a thin broth.
Is this recipe Whole30 compliant?
Yes, as written it is Whole30 compliant. Just check the label on your Montreal steak seasoning — most commercial blends are compliant, but a small number contain sugar or anti-caking agents that aren’t allowed on Whole30.
Can I prep this the night before?
You can season the roast and store it uncovered in the fridge overnight, which gives the seasoning more time to penetrate the meat. Cut the hardy vegetables — carrots and red onion — and refrigerate them separately. The delicate vegetables are best cut fresh the next morning so they don’t weep overnight.
More recipes to try
- Hearty Shepherd’s Pie
- Elegant Chicken Marsala with Mushrooms
- Caramelized Brussels Sprouts with Balsamic Glaze
- Sweet Corn Chowder
