Preheat the oven to 400 degrees F.
Remove the husks from the tomatillos, rinse them, and dry. Place them on a baking sheet, along with the jalapenos. Drizzle these with the olive oil, tossing everything around on the pan to ensure they’re evenly coated. Place in the oven and roast for 15 minutes.
When those are done, remove the stem from the jalapenos. Place the jalapenos, red onion, and cilantro in a small food processor bowl. Pulse several times until these are finely chopped.
Add the tomatillos, lime, and salt to the food processor bowl. Pulse a couple times until it reaches the desired texture.
Pour into a bowl and stir in the chopped mango. Enjoy now, or store in the fridge for up to 4-5 days.