Cut the avocados in half, remove the pit, and scoop the flesh into a mixing bowl.
Use a fork or potato masher to mash the avocado to your desired level of creaminess.
Add the diced tomato, chopped onion, minced garlic, lime juice, salt, and pepper to the mashed avocado.
If desired, add chopped cilantro and jalapeño for an extra kick.
Gently mix all ingredients until well combined but still chunky.
Taste and adjust seasoning if needed, adding more lime juice, salt, or pepper as desired.
Transfer the guacamole to a serving dish and serve immediately with tortilla chips or fresh vegetables.
To prevent browning, store guacamole in an airtight container with plastic wrap pressed against the surface before sealing.