Dip the cleaned peppers in boiling water for 2-3 minutes, but no longer. Finely chop the horseradishes and chervil. Prepare a brine from 1 gal (4 liters) of water, the salt and vinegar. Boil it and allow it to cool to body temperature.
Arrange the blanched peppers in a dry container, gently pressing them. Put some chervil, horseradishes, bay leaf and black pepper between them. Pour the brine over the peppers and add the mustard seeds on top, you can even place it in a small bag.
Wrap the container tightly with parchment paper and store it in a room with a constant temperature of 69.8°F (21 °C). Then strain the brine, arrange the peppers in jars, and between them, put lemon slices.
Boil the brine with mustard seeds again and strain after it cools. Pour it over the pickles and top with 1 finger width of oil.
After a week, these pickles are ready to eat. Macedonian pickled peppers are ideal as a stuffed appetizer.