Heat a large skillet over medium heat for a few minutes. Add the oil.

Add the gnocchi to the skillet and arrange them in an even layer. Season with salt. Sear the gnocchi for 4 to 6 minutes, until a golden crispy crust forms on the bottom.

Flip the gnocchi and continue cooking for 3 to 4 more minutes on the other side. Transfer the gnocchi to a plate or tray to cool.

In a large mixing bowl, add a hefty pinch of salt, a few cracks of black pepper, mayonnaise, yogurt, the zest and juice of 1 lemon, grated garlic cloves, dill, and chives. Whisk until combined.

Rinse the onion under cold tap water to reduce its sharpness, then add it to the bowl along with the celery, Serrano pepper (if using), and cooked gnocchi. Mix everything to combine. Taste and season with more salt if needed.

Serve right away or store in the fridge for later.