To prepare the lentil salad with feta, start by cooking the lentils. Drain the soaked masoor. Cook on stove top / pressure cooker or Instant pot until just cooked and retaining its shape. For pressure cooking, place masoor with enough water to cover, a bay leaf and 1/2 tsp salt. Close the pressure cooker lid and remove the weight. After a few minutes, steam starts escaping from the nozzle. Switch off after 5 minutes.
Open lid and drain the cooked lentils in a colander. Allow to cool for a bit.
Wash and dry the greens (spinach or any other).
In a shallow bowl, layer half the lentils. Scatter spinach leaves, beet, cucumber and apple over this. Top with the remaining lentils.
Scatter feta cubes over the salad.
In a small bowl, whisk the lemon juice, olive oil, turmeric and salt vigorously until thick. Pour this all over the salad.
Garnish with toasted cumin seeds and nasturtium petals.