Salsa Roja — Comal-charred tomato and árbol

Heat a dry comal or cast-iron skillet over high heat. Place the whole tomatoes, onion rounds, and unpeeled garlic directly on the comal. Char on all sides, turning with tongs, until the tomatoes are soft and blackened in spots, the onion is charred at the edges, and the garlic is soft in the skin — about 8–10 minutes. Peel the garlic.

On the same comal, toast the árbol chiles for 20–30 seconds, pressing flat and turning once. They should puff slightly and smell toasted — do not let them blacken or the salsa will be bitter.

Transfer all the charred vegetables and the toasted chiles to a blender. Add the salt. Blend on high for 20–30 seconds until smooth but with some texture remaining. Do not over-blend — the salsa should not be watery.

Heat the oil in a saucepan over high heat until shimmering and just beginning to smoke. Pour in the blended salsa — it will spit aggressively. Stand back and have a lid ready.

Fry the salsa, stirring constantly, for 3–4 minutes until it darkens slightly and the oil appears around the edges. The color deepens from bright red to a darker brick red. This is the 'freír la salsa' step and it transforms the flavor.

Remove from heat. Taste and adjust salt. Add cilantro if using. Serve hot or at room temperature. The salsa keeps refrigerated for up to 5 days.