Place the vinegar, sugar, garlic, fennel seeds and peppercorns into a saucepan and heat everything together for 5 minutes or until all of the sugar has dissolved. Remove the pickling liquid from the heat and allow to cool completely.
In a medium-sized saucepan, add the eggs and enough cold water to just cover them. Turn the heat on and bring the water to a gentle simmer. Once the water is simmering, cook the eggs for 10 minutes.
Once the time is up, remove the eggs from the hot water and instantly plunge them into cold water to stop them cooking further. Allow them to sit in the cold water for a few minutes until cool to the touch.
Once eggs are cool, peel the shells off of them and place them into a clean jar.
Place the fresh thyme and fresh tarragon into the jar and pour over the cooled pickling liquid, making sure it completely covers the eggs. Seal the jar and leave it for at least 1 week in a cool, dark place before consuming. Once opened, keep the pickled eggs in the fridge and consume within 2 weeks.