Proof the gelatin with 1 cup of cold chicken stock. Bring the remaining chicken stock, Madeira, and Tabasco to a simmer. Add the mixture to the proofed gelatin and cool to room temperature, stirring frequently.
Pour the cooled gelatin into the rimmed baking sheet and chill overnight.
Prepare the Remaining Salad Ingredients
Boil the potatoes, unpeeled until the point of a knife slides in with ease. Do not overcook them — you want them to keep their shape. Chill them for at least 2 hours, then peel and cut them into a fine dice.
Dice the carrots then toss them with olive oil and sprinkle them with salt. Roast them for 15 minutes in a 450ºF/220ºC oven. Let cool completely.
Plunge the frozen peas into a small saucepan of rapidly boiling, salted water. Let simmer for 1-2 minutes. Drain, then immerse in a small bowl with ice water. This will help stop them cooking and retain their brilliant bright color.
Fry the bacon lardons/pancetta until the fat is rendered. Remove to a plate covered with a paper towel to drain.
You can prepare these ingredients 1-2 days before, keeping them in the refrigerator in a non-reactive bowl covered with plastic wrap.
Make the Sauce several hours before serving
Combine the garlic cloves, anchovy fillet, mustard, lemon zest, capers, and shallot with one tsp. of salt in a food processor fitted with a steel blade. Pulse to combine into a rough paste.
Add the egg yolks, then slowly add the olive oil in a fine drizzle until the mixture thickens.
Taste and adjust seasoning with Tabasco, salt and pepper.
Chill for at least 3 hours to allow the flavors to combine and bloom and the texture to thicken.
Assemble the Salad:
Decant the cornichons from their jar, drain well and cut into cubes.
Toss the salad ingredients lightly with approximately three-quarters of the sauce.
Taste to adjust seasoning with salt and pepper and perhaps a bit more sauce. The sauce should lightly coat the ingredients, not drown them.
Remove the aspic from the refrigerator and gently slice into small cubes. Don’t worry if these don’t hold their shape — the taste is the main thing. Return to the refrigerator until you are ready to serve.
As gently as you can, fold the gelatin cubes into the salad.
Garnish with Parsley and Chives
My preferred method for serving Salad Olivier is to scoop small amounts into pastry cups, individual china ramekins, small ceramic serving spoons, or in small shot glasses. The presentation looks better than a massive mound of potato salad, and single servings won’t slip and slide as much as the evening progresses. Of course, when the evening is over, all bets are off, and the dish reverts to the comfort food/hangover blotting paper it’s meant to be!
Duck Confit and Pancetta can be hard to find, but the search is worth it. I get mine online from D'Artagnan.