Preheat oven to 400°F. Coat a baking tray with 2 tbsp of olive oil (wait to use the third tbsp until the last step). Arrange the poblano peppers, serrano peppers and garlic cloves on tray. Bake for 30 minutes, flipping once halfway.
Place poblano peppers in a bowl and cover with lid or plastic wrap. Let them rest for 20 minutes.
Once the poblano peppers have cooled down, remove their skin and seeds. Halve the serrano pepper and remove seeds to reduce spiciness level if preferred.
Transfer poblano peppers, serrano pepper and garlic to a food processor. Add the rest of the ingredients and puree until smooth. Enjoy!