Remove the stem area from the tomatoes. Slice the white onion, keeping the root so the layers stay together.

Heat a comal over medium heat. Once hot, roast the tomatoes, serrano, onion, and unpeeled garlic until charred and blackened on all sides. Remove each ingredient as it finishes roasting and is fully cooked through.

In a molcajete, peel the roasted garlic and mash it with the raw garlic clove and a pinch of salt until smooth. Cut off the onion root, then grind the onion, followed by the pepper, and finally the tomatoes. 

Work each one in until broken down. The salsa should be smooth but still chunky. Season with salt to taste and mix well.

Finish by stirring in chopped fresh onion and cilantro.

Preheat the oven to 425ºF. Remove the cores from the tomatoes and cut them in half. Slice the white onion into thick pieces. Remove the stem from the serrano and make a small slit in the center.

Place the tomatoes, onion, unpeeled garlic clove, and serrano on a parchment-lined sheet pan. Drizzle lightly with oil and cook in the oven for 20–25 minutes, or until softened and lightly charred. 

Set aside the most charred pieces, then broil the remaining ingredients on high for 3–5 minutes to add more browning.

Let everything cool slightly. Transfer to a blender, peel the roasted garlic, and add one small raw garlic clove for extra flavor. 

Blend with 1/2 cup of water for a runnier salsa, or skip the water for a chunkier texture. Blend to your preferred consistency and season with salt to taste.

For tacos, skip the fresh cilantro and onion. For other dishes, feel free to add them for more texture and freshness.