Ingredients :

• The shrimp — Cooked or raw, both work. Raw ones give a slightly firmer texture and a more pronounced flavor — if you find good ones at the fishmonger, go for it. Otherwise, frozen cooked shrimp are honest enough, provided you drain them well and dry them on paper towels before use. Moisture is the enemy of the sauce.
• The avocados — This is the ingredient that can ruin everything if you get the ripeness wrong. Press lightly on the tip — it should give very slightly without sinking in. Too soft, and it’s mash. Too hard, and it’s wood. If yours are still firm, leave them overnight at room temperature with a banana nearby — it really speeds things up.
• The mayo + yogurt sauce — The yogurt lightens the mayonnaise without betraying it. You keep the creaminess and the binding, but without the heaviness. Use a standard plain yogurt, not 0%, otherwise the sauce becomes a bit watery. The mustard isn’t there to be tasted — just a teaspoon to give depth to the whole thing.
• The shallot — Less aggressive than red onion, more elegant in the mouth. Mince it very fine — we want it to melt into the sauce and provide a slight spicy hint, not to chew on it. If you don’t have any, a red onion does the job, but cut it even finer and rinse it quickly with cold water to tone down the heat.