Place the 3 lb papas Yukon Gold cortadas en trozos de 3/4-pulgada, con piel o peladas chunks in a large Pot and cover with cold water by at least 1 inch. Add a generous pinch of 1 tsp sal más para el agua de cocción. Bring to a boil over high heat, then reduce to a steady simmer.

Cook the 3 lb papas Yukon Gold cortadas en trozos de 3/4-pulgada, con piel o peladas for 12–15 minutes, until fork-tender but not falling apart. You want them to hold their shape. Drain in a Colander and spread out on a Baking Sheet or large plate to cool for 15–20 minutes. Do not rinse — the starch helps the dressing cling.

While the 3 lb papas Yukon Gold cortadas en trozos de 3/4-pulgada, con piel o peladas cook, hard-boil your 4 eggs huevos duros, pelados y picados aproximadamente: place them in a small Saucepan, cover with cold water, bring to a boil, then cover and remove from heat. Let sit for 12 minutes, then transfer to an ice bath. Once cool, peel and roughly chop.

In a medium Mixing Bowl, whisk together the ¾ cup mayonesa, ¼ cup crema agria, 1 ½ tbsp mostaza amarilla, 1 tbsp vinagre de sidra de manzana, 1 tbsp salmuera de encurtido del frasco de encurtidos, 1 tsp azúcar, ½ tsp ajo en polvo, 1 tsp sal más para el agua de cocción, and 1 tsp sal más para el agua de cocción until smooth and well combined. Taste and adjust seasoning — it should be creamy, tangy, and well-seasoned.

Once the 3 lb papas Yukon Gold cortadas en trozos de 3/4-pulgada, con piel o peladas have cooled to room temperature (or are just slightly warm), transfer them to a large Mixing Bowl. Add the chopped 4 eggs huevos duros, pelados y picados aproximadamente, diced 3 stalks apio picado finamente, 0.5 cebolla roja picada finamente, and 3 tbsp encurtidos picados finamente, más 1 tbsp salmuera de encurtido.

Pour the dressing over the 3 lb papas Yukon Gold cortadas en trozos de 3/4-pulgada, con piel o peladas mixture and gently fold everything together with a Spatula or large spoon, being careful not to mash the 3 lb papas Yukon Gold cortadas en trozos de 3/4-pulgada, con piel o peladas. Fold in the 3 tbsp cebolletas frescas cortadas en rodajas finas if using.

Taste and adjust 1 tsp sal más para el agua de cocción, 1 tsp sal más para el agua de cocción, or a splash more 1 tbsp vinagre de sidra de manzana as needed. Cover and refrigerate for at least 1 hour (or up to overnight) before serving — this rest time is essential for the flavors to develop.

Before serving, give the salad a gentle stir. Garnish with fresh 2 tbsp perejil fresco picado, para adornar and a dusting of ½ tsp paprika dulce o ahumada, para adornar. Serve cold.