Cut the tomato and onion into quarters then season with salt and pepper.
On a grill preheated to a medium temperature then grill the tomato, onion, jalapeno, and garlic until soft. About 10 minutes.
Place the grilled tomato, onion, jalapeno, and garlic in a blender. Blend until smooth.
In a skillet preheated to a medium temperature add the olive oil. Add the blended tomato mixture then simmer for two minutes.
Add the beer to the tomato mixture and bring to a boil. Continue to cook until it had reduced to your preferred consistency, this takes about 10 minutes.
Remove from the heat and transfer to a bowl. Stir through the diced cilantro (coriander). Chill then serve garnished with additional cilantro.