Chef John's Perfect Margarita

Killing some time on this lovely Cinco De Mayo and giving Chef John's Perfect Margarita a try.

4 oz Tres Agaves tequila. They were giving out free samples and it seemed like it would work perfectly, and it did. I flirted with the lady who was giving out samples and I'm going to pretend she appreciated it.

3 oz Cointreau. I asked the tequila lady where the triple sec was, and she didn't know. It was probably about 3 feet away from her. Isn't it her job to know these things? Actually, it's not. I asked. She said "I only do one thing."

2 oz fresh lime juice. I don't really have a story about the limes, except it was 2 dollars for 3 limes which seems a little ridiculous.

 Shake with ice, strain into a chilled container of your choice over ice. Salted rim optional but highly recommended. I used some pretzel salt from Denver Spice which actually worked out pretty great, but some regular kosher salt will do you just fine.