In search of... por favor

I was on a similar mission a few weeks ago. You’ll likely find two “mints”, mentha and hierbabuena, with the latter being far more prevalent among the many stalls along the streets outside and behind the Mercado Municipal (I only found mentha at one place). I tried both, and preferred the hierbabuena in our mojitos

You can find the location of the Mercado Municipal online, and then decide if you might prefer to taxi over from your perch. It’s a wonderful experience roaming around and taking in the vast variety of food and other things for sale! Just find stalls where you see bunches of fresh herbs and ask if they have some hierbabuena.