My favorite guac recipe is adapted from Alton Brown's recipe. Everyone RAVES about it.
3 avocados, halved, seeded and peeled
1 lime, zested and then juiced
1 small jalepeno, seeded and minced (leave the seeds in in you like it hot)
1/2 teaspoon kosher salt
1/2 teaspoon ground cumin
1/2 teaspoon cayenne
1/2 teaspoon chili powder
1/2 medium red onion, diced
2 Roma tomatoes, seeded and diced
1 tablespoon chopped cilantro
1 clove garlic, minced
In a large bowl place the scooped avocado pulp and lime juice and zest, toss to coat. Using a potato masher add the salt, cumin, and cayenne and mash to your desired consistency (I leave it a slightly chunky). Then, fold in the onions, tomatoes, jalepeo, cilantro, and garlic. Let sit at room temperature for 1 hour and then serve.