In a large bowl, whisk the eggs and heavy cream until light and frothy.
Stir in the black pepper, chili powder, sea salt, spinach, 1/4 cup (960 ml) red onion, bell pepper, and shredded cheddar cheese until just combined.
Lightly grease a 7-inch round baking dish with olive oil.
Pour the egg mixture into the prepared dish.
Pour 1 cup (240 ml) of water into the inner pot of your Instant Pot and place the trivet inside. Carefully lower the baking dish onto the trivet.
Secure the Instant Pot lid, set the steam release valve to 'Sealing', and cook on High Pressure for 12 minutes.
Once the cooking cycle is complete, allow the pressure to release naturally for 15 minutes. Perform a quick release for any remaining pressure once the floating valve drops.
Carefully remove the lid and lift the baking dish out of the Instant Pot.
Let it cool for a few minutes before topping.
Top the warm frittata with diced tomato, the remaining chopped red onion, avocado, dollops of sour cream, crushed jalapeno, and a sprinkle of spring onions.
Slice and serve warm.