Rinse the cod roe and then wrap the cod roe in baking paper (this prevents it from bursting during cooking).
Place the parcel in a saucepan with cold water, onion, celery, fennel seeds, bay leaves, salt and peppercorns. Next, bring the water to just below boiling point and ensure it simmers gently for approx. 25–30 minutes, depending on the size of your roe. Leave the cod roe to cool in the saucepan with the liquid.
You can actually eat the cooked cod roe as it is, or follow the recipe here and slice it, then coat in a little flour. The slices can then be fried in a pan with olive oil and butter on both sides until golden and crispy.
Place the egg yolks in a large bowl together with the mustard, 1 tbsp vinegar, a little salt and pepper, and whisk well using a whisk or an electric hand mixer.
Now whisk the oil into the egg yolks a little at a time in a thin stream. Pour slowly enough that the oil is constantly being whisked into the egg yolks. Pause occasionally whilst adding the oil and whisk the mayonnaise thoroughly.
Continue until all the oil has been added, then whisk in a little water.
Whisk thoroughly again – this helps to ensure that the mayonnaise doesn’t separate and that it has a nice, smooth consistency.
Finally, season to taste with salt and, if desired, a little extra vinegar. Place the mayonnaise in the fridge immediately, where it will keep for 4–5 days.
Chop the hard-boiled eggs, pickled gherkins, shallots, capers and tarragon.
Mix everything together with mayonnaise, crème fraîche and Dijon mustard, then season to taste with lemon juice, salt and pepper.
Slice the fennel into crudités using a mandoline and place them in a bowl of ice water to make them extra crisp.
If you haven’t fried your cod roe, you could fry your slices of rye bread in butter. Otherwise, spread a generous amount of tartar sauce (whatever your preference) on the rye bread and then place your cod roe on top. Top with a little more tartar sauce. Toss the fennel crudités with a little of your homemade vinaigrette (you can find the recipe here) and arrange on top along with dill, then season with lemon juice to taste. EAT.
