Rinse the Poblano peppers under cold water and place them on a baking sheet. Roast at 400°F for about 30 minutes, turning halfway through, until blistered and charred.

In a blender, combine the roasted Poblanos, chopped onion, garlic, cilantro, and optional spinach. Add a splash of vegetable stock and blend until smooth.

Heat olive oil in a medium saucepan over medium heat. Add rice and sauté for 2-3 minutes until opaque and lightly golden.

Add the blended green mixture to the sautéed rice. Stir together and cook for an additional 2 minutes.

Pour in vegetable stock and add salt. Stir well and bring to a boil. Reduce heat to low and simmer.

Cover and cook undisturbed for 15-20 minutes until the liquid is absorbed.

Remove from heat and let sit covered for an additional 5 minutes. Remove lid and adjust salt if necessary.