Preheat your oven to 400°F (200°C).

Wash the tomatoes, jalapeños, and cilantro thoroughly under running water.

Place the tomatoes, jalapeños, onion (halved), and unpeeled garlic cloves on a baking sheet. Drizzle with olive oil and toss to coat evenly.

Roast the vegetables in the preheated oven for 15-20 minutes, or until the tomatoes and jalapeños are blistered and slightly charred.

Remove the baking sheet from the oven and allow the vegetables to cool for a few minutes.

Peel the garlic cloves and discard the skins.

Add the roasted tomatoes, jalapeños, onion, peeled garlic, cilantro, ground cumin, lime juice, and a pinch of salt to a blender or food processor.

Pulse the mixture several times until you achieve your desired salsa consistency (chunky or smooth). Taste and adjust the salt, cumin, or lime juice as needed.

Transfer the salsa to a bowl and serve immediately with tortilla chips or as a topping for tacos, burritos, or grilled meats.