Preheat your grill on medium high heat.
Slice avocados in half, remove pit.
Place avocados and onion cut side down on grill. Place jalapeno and whole garlic on the grill as well. Grill for 4 - 6 minutes until grill marks form.
Allow avocados and vegetables to cool and then dice the onion and press the garlic using a garlic press.
Add avocados to a mixing bowl.
Mash the avocados with a fork until desired texture. Add garlic and stir.
Add onion and jalapeno to the avocados. Stir to incorporate.
Stir in lime juice, cilantro and salt. Taste to check for seasoning.