Fillet the eel and then dust the obtained fillets with flour.

Heat some Extra Virgin Olive Oil in a pan and fry the eel fillets until golden brown. Drain them on paper towels to remove excess oil.

Meanwhile, prepare the red onion reduction: in a saucepan, place the julienned red onion and add apple cider vinegar, white wine, salt, and sugar. Bring to a boil and let it cook until the liquid has reduced to a thick consistency. Taste and adjust seasoning if necessary.

Pour the red onion reduction over the golden brown eel fillets and let them rest to blend the flavors.

To prepare the pickles, cut the vegetables into regular pieces and cook them in salted and acidulated water until tender but still crisp. Drain them and dry them on a clean cloth.

In another pot, bring to a boil a solution of water, vinegar, sugar, salt, and desired spices.

Place the drained vegetables in a glass jar and cover them with the freshly prepared solution. Seal the jar tightly.

Proceed with sterilizing the jar by boiling it in water for about 20 minutes.

Once sterilized, let the jar cool before storing it in the pantry.