Drain the lentils. Slice the grilled peppers into strips, cut the beetroot into wedges. Rinse and drain the spinach.
Rub the meat on both sides with oil and season with salt.
Heat a frying pan. When it is hot, almost smoking, fry the steak on both sides for 1 to 5 minutes, turning it several times (once every minute).
When it’s done to your liking, transfer the steak to a plate and rest for 5 minutes under cover.
In the frying pan heat through the lentils, then add the beetroot, pepper slices and the spinach.
When the spinach leaves have wilted, season with salt and pepper, then urn off the heat.
Divide the mixture between two plates.
Slice the steak and place them on top the lentil salad.
Scatter some mint leaves over the dish and serve.