Use a fork or potato masher to mash the avocado to your preferred texture — slightly chunky (leave some pea- to marble-sized pieces) or smooth. Do not overwork; a bit of texture is desirable.

Add aromatics

Add the finely diced red onion, minced jalapeño (taste first; include seeds if you prefer more heat), and chopped cilantro to the mashed avocado. Fold gently to combine.

Season and finish

Stir in the fresh lime juice, sea salt, and ground black pepper. If using, add the diced tomato and a pinch (1/8 tsp) of ground cumin. Taste and adjust seasoning — add more lime or salt as needed.

Rest briefly

Let the guacamole sit at room temperature for 5–10 minutes to allow flavors to meld before serving. If serving later (up to 2 hours), cover tightly with plastic wrap pressed directly onto the surface to minimize browning and refrigerate.

To Serve

Transfer guacamole to a serving bowl. Garnish with extra cilantro leaves and a light drizzle of lime juice if desired. Serve with tortilla chips and lime wedges alongside.