- Cook lentils according to package instructions. Drain well. While lentils are cooking, combine lemon juice, olive oil, onion and salt and pepper in a bowl. Toss well with warm lentils and set aside.
- Chop beet greens - both stems and greens - into bite-sized pieces. Heat olive oil in a large fry pan. Add greens and salt – greens will spatter briefly. Stir continuously until colours brighten and leaves just become wilted, about 2 minutes. Stir in garlic and chilli flakes and sauté 30 seconds more. Stir balsamic vinegar through leaves and remove pan from the heat.
- Add lentils to greens along with herbs. Season with salt and pepper and taste. Adjust seasoning if necessary. Top with feta if desired.
Many different greens will work in this recipe: spinach (trim any long stems), kale (discard the tough spine), swiss chard or mustard greens.
Serve this dish straight up or alongside something more substantial, like pork medallions with apples and cream.