This dressing is based on the classic French sauce called gribiche, and can accompany vegetables as it does here, but is also pretty terrific spooned over crispy-skinned fish or roasted salmon. Use medium- or thick-stalked asparagus for heft — pencil-thin asparagus would get upstaged.
Peel and mince shallot; transfer to a medium bowl and season with salt.
Juice lemon into a small liquid measuring cup. Add enough vinegar to measure 80 ml in total. Pour lemon-vinegar mixture over shallot. Set aside while you prep the remaining ingredients.
Thinly slice the cornichons into rounds and place in a small bowl. Smash and pit the olives, then tear into small pieces; add to the bowl. Pluck the parsley leaves with some tender stem attached, then gather them up on your cutting board and thinly slice into ribbons (save the remaining parsley stems for making stock). Set cornichon-olive mixture and parsley aside separately.
Bring a medium pot of water to the boil over high heat; fill a medium bowl with ice and water. Lower eggs into boiling water and cook for 7 minutes for jammy yolks. Use a slotted spoon to transfer eggs to ice water and let cool; reserve both ice water and boiling water.
Snap off woody ends of the asparagus, then peel bottom two-thirds of stalks. Season boiling water very generously with salt. Add the asparagus and cook until bright green and crisp-tender, 3 minutes. Transfer to ice bath to cool, then pat dry with a clean tea towel and arrange on a platter.
Peel and quarter eggs. Arrange them on and around asparagus. Whisk mustard into shallot mixture, then slowly whisk in olive oil (it won’t completely emulsify, but the mixture should thicken). Stir in cornichon/olive mixture and parsley. Taste dressing and adjust with salt and pepper; spoon over eggs and asparagus.
The eggs and asparagus can be cooked several hours in advance; then covered and refrigerated. The dressing (without parsley) can be made up to a day in advance; cover and refrigerate. Stir in parsley right before serving.
Recipe adapted from: That Sounds So Good (Hardie Grant)