One of our fondest childhood memories is of long, lazy days by the sea, lulled by the sound of the waves and the soft caress of the breeze. It was a state of bliss, marred only by the idleness of our taste buds. Thankfully, a roaming army of beach vendors came to the rescue, offering amusement in the form of golden potato chips—crisply fried in olive oil and seasoned with sea salt.

These memories came rushing back when our friend Raul Reis called to say he was bringing over a sack of potatoes. Raul grows Portugal’s finest potatoes in the quiet village of Sobral on the west coast. This time, he arrived with a bag of bricatas, cultivated in soil enriched with algae from the nearby beach of Porto Dinheiro.

Porto Dinheiro is best known for its vacada, a rustic summertime tradition that draws crowds to watch cows and bulls frolic on the beach. Before the event, the beach must be cleared of the algae that regularly washes ashore. Left in piles, the algae would rot and release a pungent smell. Raul had a better idea—he proposed to the mayor that he take the algae back to his farm as fertilizer. Everybody gained: Raul found a natural way to enrich his soil, and the town rid itself of a nuisance.

Five trucks, each carrying 20 tons, made the journey from Porto Dinheiro to Sobral. Raul allowed the algae to ferment for three weeks, turning the piles weekly to aerate them. He then spread the seaweed across his fields, tilling it into the soil before the summer winds could carry it away.

Using algae to nourish the land is an ancient Portuguese practice, nearly forgotten in the era of synthetic fertilizers. In Aveiro, whole fleets of moliceiros—graceful, flat-bottomed boats—once glided through the marshes gathering seaweed for the fields.

We sliced the bricata potatoes into delicate spirals, fried them until perfectly crisp, and sprinkled them with sea salt. They were, without question, the best potato chips we’ve ever had. You can try them too at Canalha, João Rodrigues’ wonderful restaurant in Lisbon, or at Alta, where the food is as delightful as the sea views. A plate of these golden chips is a summer vacation for the palate.