Heat a large cast iron skillet over medium-high heat. Add the Roma tomatoes, chopped white onion, and halved jalapeño pepper to the skillet. Cook these ingredients for about 5 minutes, turning them occasionally until they are nicely charred on all sides.

Once the vegetables are beautifully charred, carefully transfer them to a food processor. Add the drained canned whole tomatoes, garlic cloves, fresh cilantro, lime juice, ground cumin, and sugar if desired.

Secure the lid on the food processor and blend the mixture until you reach your desired consistency. For a chunkier salsa, pulse a few times rather than blending continuously.

Once blended, taste the salsa and add kosher salt and freshly ground black pepper to your preference. Mix thoroughly to ensure even seasoning throughout.

Serve the salsa immediately with crispy tortilla chips or use it as a topping for tacos or grilled chicken.