**I’d choose freezing**, in small portions. University of Illinois Extension specifically lists papalo among the herbs best preserved this way. Expect softer leaves after thawing; freezing preserves a usable seasoning, but the fresh garnish texture will change. ([Illinois Extension](https://extension.illinois.edu/blogs/turnip-beet-nutrition-and-wellness/2016-08-22-its-thyme-preserve-those-herbs), [Penn State Extension](https://ucanr.edu/sites/default/files/2020-10/337965.pdf))

For your harvest, I’d start with **whole leaves frozen plain**:

1. Pick healthy leaves, remove the stems, rinse under running water, and gently pat or spin dry.
2. Spread the leaves in a single layer on a baking sheet and freeze.
3. Once frozen, promptly transfer them to freezer bags. Press out excess air, seal, and label with the date.
4. Take out only what you need and keep the rest frozen. ([Maryland Extension](https://extension.umd.edu/resource/harvesting-and-preserving-herbs))

This gives you flexibility when using papalo in different dishes. My suggestion is to freeze a small test batch first, then taste it in your usual salsa or other dish a few days later before committing the whole harvest.

**Freezing chopped papalo in oil is another useful option** if oil suits your recipes. Apply Penn State’s general herb method: mix **2 cups chopped leaves with ⅓–½ cup oil**, portion into small freezer containers or ice-cube trays, and freeze immediately. Transfer frozen portions to a sealed freezer container. A neutral oil lets the herb’s flavor dominate. This recipe is general herb guidance; it isn’t a papalo-specific flavor study. **Keep the mixture frozen; fresh herbs in oil should never be stored at room temperature.** ([Penn State Extension](https://ucanr.edu/sites/default/files/2020-10/337965.pdf))

For winter and some of next year, keep it at **0°F / −18°C or colder** and plan to use it within **one year**. That is Minnesota Extension’s general recommendation for frozen herbs; papalo’s flavor may fade sooner. Good packaging and small portions will help you avoid repeatedly thawing the supply. ([Maryland Extension](https://extension.umd.edu/resource/harvesting-and-preserving-herbs), [Minnesota Extension](https://extension.umn.edu/garden-and-home/yard-and-garden/gardening-in-minnesota/growing-herbs))