Step 1:

• Grease a 7-inch baking pan with cooking spray and line the bottom with parchment paper if available. If not, generously grease the pan.

Step 2: 

• Select the sauté function on the Instant Pot, add olive oil, and when it’s hot, add diced bacon.
• Cook for about 4 minutes, then add onion and bell pepper and cook for 1 to 2 minutes more.
• Remove bacon and veggies, wipe the inner pot, and add 1 cup of water.

Step 3:

• Whisk eggs in a bowl until blended.
• Add spinach, cheese, salt, pepper, sautéed bacon, onion, and bell pepper. Mix well.
• Pour the egg mixture into the prepared baking dish and top with sliced tomatoes.
• Place the baking dish on a trivet and lower it into the Instant Pot.
• Secure the lid, set to high pressure, and cook for 12 minutes.
• Allow natural pressure release for 10 minutes, then manually release remaining pressure.

Step 4:

• Carefully remove the frittata from the Instant Pot and let it stand for 5 minutes.
• Serve in the pan or transfer to a plate. Garnish with green onions and sour cream if desired.