Prepare Avocados:Scoop the avocado flesh into a mixing bowl. Mash with a fork or potato masher until smooth or leave it slightly chunky, depending on your preference.
Add Lime Juice:Stir in the lime juice to add tanginess and prevent the avocados from browning.
Mix in Ingredients:Add the red onion, garlic (if using), cilantro, salt, cumin (if using), and jalapeño (if desired). Mix until well combined.
Taste and Adjust:Taste the guacamole and adjust the seasoning with more salt or lime juice as needed.
Serve:Transfer the guacamole to a serving bowl. Garnish with extra cilantro or a lime wedge, if desired. Serve immediately with tortilla chips, fresh veggies, or as a topping for tacos or burritos.