Fill a medium saucepan three-quarters full with water and bring to the boil. Add the rice and cook for 25-27 mins until tender. Drain.
Step 2 — Pickle carrot
Meanwhile, peel the carrot into ribbons with a vegetable peeler. Combine 3 tsp white vinegar, 1½ tsp sugar and ¼ tsp salt in a large bowl. Add the carrot and toss to combine. Set aside to pickle, tossing occasionally, until needed.
Step 3 — Stir-fry beef
Separate the beef stir-fry. Heat 2 tsp vegetable oil in a large frypan over high heat until very hot (see Kitchen notes). Stir-fry the beef for 1-2 mins until browned.
Step 4 — Add sauce and spinach
Add the stir-fry sauce to the beef and stir-fry for a further 1-2 mins until heated through. Add the spinach and toss until slightly wilted. Remove the pan from the heat.
Step 5 — Serve up
Coarsely chop the peanuts. Divide the rice, beef stir-fry and drained pickled carrot among bowls. Scatter over the peanuts and enjoy!
Step 6 — Kitchen notes
Ensuring the pan is really hot before adding the beef prevents it from stewing and gives it a nice browned finish. ~ Add a kick with a pinch of chilli flakes, or boost the freshness with a scattering of thinly sliced spring onion, if you have some on hand.