Place diced onions, leeks, shallots into the Instant Pot and drizzle with 2 tablespoons of olive oil.
Turn on the saute function of the Instant Pot, cooking until soft and translucent (about 8 minutes). Stir occasionally to prevent from scorching the onions.
Add the rice and vegetable broth, cover with the lid, close the vent and set to manual, high pressure for 10 minutes.
While the rice is cooking, prepare the vegetables: peppers, zucchini, tomatoes and spinach.
In a saute pan, add 2 tablespoons of olive oil and saute the vegetables over medium heat until brightly colored and firm. Turn off the heat and allow the veggies to rest until the rice is ready.
When the timer beeps on the Instant Pot, open the vent to allow the pressure to release.
Open the lid and add the lemon juice, optional wine, oregano, basil, salt and pepper. Stir well.
If including cheese, mix it into the hot rice at this point.
Toss in the sauteed vegetables and spinach slivers and mix.