Add the lentils, rice, tomatoes, and potato/squash, if using, along with another pinch of salt and stir to incorporate. Add the water and more salt, cover, and bring up to a simmer. The amount of water you'll need will depend on whether you used rice and potato. Add a full 8 cups if using both, and start with about 6 cups if using neither. Simmer the stew for 30-35 minutes, until the lentils, rice, and potato are soft. Check the liquid level periodically and add more water if the stew becomes too thick.
Once the soup is done, turn off the heat and taste for salt and pepper, adjusting if needed. Wilt in the spinach, as much as you like. Stir in the lemon juice. Serve hot, garnished with any preferred garnishes: herbs, yogurt, pesto, or pan-fried mushrooms as pictured. Enjoy!
Recipe by Golubka Kitchen at https://golubkakitchen.com/cozy-pantry-stew/