Pack the sliced jalapenos and smashed garlic into a clean pint jar.

Combine the vinegar, water, sugar and salt in a small saucepan and bring to a simmer over medium heat, stirring until dissolved, about 3 minutes.

Pour the hot brine over the jalapenos, making sure they're fully covered.

Let cool at room temperature for 30 minutes.

Cover and refrigerate at least 1 hour before serving, or up to 3 weeks.