Start by measuring out your whole yellow mustard seeds. Use a food processor to pulse the seeds just enough to crack them open and release their flavor, then transfer them to a small bowl.

Next, chop your foraged wild mustard greens into manageable pieces. Pulse these in the food processor until they form a paste, and then add this paste to the bowl with the mustard seeds.

Mince a clove of garlic, either by hand or with a garlic press, and add it to the bowl along with a pinch of salt.

Gradually add water to the mixture, stirring until the ingredients are evenly combined. Continue adding water until the mixture is well-blended, even if it looks slightly wet—the seeds will absorb the excess moisture.

Pour the mustard mixture into a half-pint jar, cover with a lid, and place the jar in a spot with a stable room temperature. Allow the mixture to ferment for 5-7 days.

After the fermentation period, your mustard is ready. You can choose to keep the grains whole for a coarse texture or blend the mixture for a smoother consistency.

Finally, store the finished mustard in the refrigerator with the lid on. Properly fermented mustard, when kept free from cross-contamination, should stay fresh for 6-12 months.