In a medium bowl, mash the avocados using a fork until smooth but slightly chunky.
Tip: To keep your guacamole creamy and lump-free, use a potato masher or fork. Avoid over-blending to preserve texture.
Add lime juice immediately to prevent browning and infuse zesty flavor.
Stir in red onion, tomato, jalapeño (if using), and cilantro.
Sprinkle ground cumin (if desired), and season with salt and pepper to taste. Mix until well combined.