Cut the avocados in half, remove the pits, and scoop the flesh into a medium-sized bowl. Mash with a fork until you reach your desired consistency—smooth or slightly chunky.
Mix in the garlic powder, cumin, black pepper, and salt. Stir well to evenly distribute the spices.
Add the Roma tomato, cilantro, and diced red onion. Mix gently to combine all ingredients.
Taste your guacamole and adjust the seasoning if needed. Add more salt, lime juice, or cumin according to your preference.
Transfer the guacamole to a serving bowl and enjoy immediately with tortilla chips, fresh veggies, or as a topping for tacos, burgers, or salads.