Pickled Red Onion
To lightly blanch the red onion, bring a small saucepan of water to a boil; remove from the heat and add the sliced red onions. Allow to stand for a few seconds and drain; transfer to a bowl of cold water to halt the cooking process and drain again.
Place the blanched red onion in a small jar or lidded container. Meanwhile, place ½ tsp. granulated sugar, ¾ tsp. fine sea salt, ¼ c. water, ½ c. vinegar, 1 clove garlic, 5 black peppercorns, 1 bay leaf, 3 sprigs of dill and ¼ tsp. cayenne pepper in a small saucepan and bring to a simmer, stirring to dissolve the salt and sugar.
Remove from the heat and add the water–vinegar mixture (along with all of the flavorings) into the container with the onions. Allow to cool at room temperature and then refrigerate for at least 30 minutes or up to 8 hours (the pickled onions will keep in the refrigerator for up to a week or more).
Using a fork, prick holes in the eggplant at regular intervals and rub roughly half of the oil over the surface. Place on a lined sheet pan and roast in a preheated 350˚F oven for 30 to 40 minutes, or until the skin has blistered slightly and the flesh of the eggplant is very soft.
Remove the eggplant from the oven and cool. Carefully peel the skin and green stem from the eggplant. To reduce bitterness, squeeze and drain excess liquid from the flesh and discard any large pockets of seeds.
Meanwhile, heat the remaining oil in a small sauté pan and gently sweat the onion and garlic, along with the curry powder, cooking just until softened and fragrant. Remove from the heat and combine the eggplant, onion mixture, lemon juice and chopped parsley into the Electrolux Masterpiece Collection blender. Pulse until a barely smooth puree is formed.
Season the mixture with salt and pepper, and adjust the consistency with a bit more oil or lemon juice if desired. Refrigerate until assembly.
Peel each pearl onion and slice in half crosswise. Begin to heat a heavy iron skillet or sauté pan and place each onion half, cut side down, onto the dry pan. Apply moderate pressure, and cook for 2 to 3 minutes over medium heat, allowing the onion to blacken. Remove from the heat and allow the onions to cool.
Trim the root or bulb ends from each onion half and place in a saucepan cut side up and gently simmer with ½ c. water or chicken stock until tender and the stock has reduced. Glaze with 2 tsp. unsalted butter and season with fine sea salt. Reserve warm or at room temperature.
Lemon Crème Fraîche
Whisk together the crème fraîche and juice and grated zest of ½ lemon, and reserve chilled until assembly.
Arrange a herring fillet on each plate and lightly brush with vegetable oil or olive oil. Sprinkle each fillet with finely chopped fresh dill, crushed rye bread, and lemon juice and zest. Arrange a few of the drained slices of pickled onion around each fillet, followed by the charred onion, eggplant ikra, parsley leaves and additional dill. Serve alongside the lemon crème fraîche and warm boiled potato.