Slice the serrano peppers as finely as possible.

If you want a less hot outcome, leave off the seeds.

Warm the vinegar, water, maple syrup, and salt in a medium saucepan. Stir until well combined. Let to cool slightly.

Place the sliced peppers in a jar or container with a cover. Place the airtight cover on top of the vinegar mixture.

Let at least an hour to sit before serving.

This pickled serrano will keep in the fridge for about 2 weeks.