PREHEAT your oven or air fryer to 350°F/180°C.
WIPE the outside of the mushrooms clean with a damp paper towel. Gently twist off or cut the stem of each mushroom and with a spoon or dull knife, gently scrape out the gills.
BLEND the basil, spinach, garlic, scallions, lemon juice, nutritional yeast, salt, chili flakes, extra virgin olive oil, and water in a small food processor until you get a rough paste.
LAY your portobello caps—facing up—inside a lined baking sheet or air fryer tray/basket and season with salt.
SPOON your herb mixture into each mushroom cup (you may have herb mixture leftover depending on the size of your mushrooms) then gently crack one egg into each mushroom and season with salt and pepper to taste.
BAKE your mushrooms for 12 to 15 minutes or air fry for 8 to 10 minutes.
SERVE immediately.