Prepare your vegetables. Cut the zucchini, oniuon, and peppers into chunks.
Preheat a large skillet to medium-low heat. Add the olive oil. Slice the garlic cloves and cook them for 2 minutes, stirring to keep the garlic from burning. Add the onion chunks and red pepper flakes and cook for another 5 minutes, stirring often.
Add the bell peppers and cook for another 8 minutes. Add the zucchini chunks and cook for 10 minutes, stirring often so the vegetables will poach.
Add the canned diced tomatoes and salt, pepper, and Erythritol. Stir to combine and continue to simmer on medium-low heat for 15 minutes. The pisto will thicken.
Serve hot topped with a freshly cooked fried egg or top with Manchego cheese.
Feel free to add two teaspoons of cumin for additional flavor. You can also add some oregano or parsley.