You need to pick the closed flower buds. These are the buds before they bloom. After blooming, dandelion forms similar looking 'buds' where the puff seeds are formed, so make sure you are dealing with unopened flower buds rather than seed buds. If you are in doubt, squeeze the bud gently between your index finger and thumb. You should see the yellow petals.
Fill a glass jar with the dandelion buds. Cover with vinegar. If you want to create a fuller flavour, use a home made vinegar. You can use any wild green vinegar, a wild flower vinegar, and even spruce vinegar.
Next, add some herbal salt. For one cup I used 1,5 tablespoon of herbal salt.
Close the jar and let stand for 6 to 8 weeks. I know I mention this over and over again, but if the lid of your jar is metal, don't forget that vinegar acts corrosive. Avoid the vinegar eating your lid (and spoiling your capers) by placing a piece of parchment paper between the lid and the contents of the jar.
This tastes great in salads, on wild pizzas, dips or spreads.