Not just for cowboys, packaged dried beef makes a wonderful starter for this dip, with smoky adobo chiles, toasted pecans, and melted Monterey Jack cheese.
For maximum heat, leave the seeds and membranes in the pepper; habanero will be much hotter than serrano. Ever touched your lips or eyes after chopping hot peppers? Avoid those burns by wearing gloves to prevent the pepper's heat from penetrating your skin.