Preheat the oven to 450°F. Line a baking sheet with parchment or foil.

Toss together tomatillos, jalapeños, olive oil, and 1/4 teaspoon salt, and put on prepared baking sheet. Roast for 20 minutes.

Let cool for about 10 minutes. Transfer to the bowl of a blender or food processor with garlic, and blend until mainly chopped up. {It will be a little soupy}

Meanwhile, mash up avocados to desired consistency. Stir in tomatillo mixture with remaining 1/2 teaspoon salt, lime juice, red onion, tomatoes, and cilantro. {Add more lime juice or salt if desired}

Serve immediately, or refrigerate for up to 2 days {the color may change, but it will still be good}