Method

1. Heat olive oil in a pan over medium heat for a few minutes or until hot.
2. Add sliced beef and cook until it browns, less than 5 minutes, don't stir too much, you want it to brown. Transfer to a plate and set aside.
3. Add onions to a skillet with butter and olive oil and cook 20 minutes until onions are caramelized and tender.
4. Add all other sauce ingredients into the skillet and stir the ingredients together over medium-low heat until it starts to simmer, about 5 minutes.
5. Use an immersion blender to blend sauce.
6. Keep the sauce warm over low heat, and add broccoli to the skillet.
7. Return beef to the pan and toss with broccoli and sauce top. Stir until everything is coated with the sauce.
8. Bring to a simmer and cook for another few minutes until broccoli is tender.
9. Season with salt and pepper to taste, if needed.
10. Serve immediately, optionally pairing with cooked cauliflower rice.