Bring 3 cups of water in a medium saucepan to a boil. Add the onions and boil for 5 minutes. Drain in a colander and refresh under cold running water. Cut away the stem ends of the onions and slip off the skins. Set aside.

Heat a saute pan or dutch oven, large enough to hold the chicken in one layer, over medium heat. Add the salt pork and cook, stirring, until brown, about 5 minutes. Remove with a slotted spoon and drain on paper towels.

Season the flour with the Essence, 1/4 teaspoon of the salt, and 1/4 teaspoon of the pepper. Lightly dredge the chicken in the flour, shaking to remove any excess. Increase the heat to medium-high. Add the chicken to the fat in the pan and cook until light brown, about 3 to 4 minutes per side. Add the pearl onions, mushrooms, and garlic and cook until onions begin to brown and the mushrooms release their liquid. Remove the pot from the heat and carefully add the cognac. With a match, ignite the cognac, return to the heat and cook for 1 minute, until flames die out and the alcohol cooks off. Add the wine and cook, stirring to deglaze the pan. Add the stock to cover the chicken and the bouquet garni, bring to a simmer, cover, and cook for about 20 to 25 minutes, or until the chicken is cooked through. Remove the chicken from the pot and place on a large serving platter.

Make a beurre manie by combining the butter with 1 tablespoon of the flour, mixing well. Return the pan with the wine to the heat and bring to a boil to reduce slightly. Remove from the heat and whisk in the beurre manie. Continue whisking until the paste has been absorbed and the sauce thickens, about 5 minutes. Reseason to taste with salt and pepper. Add the chicken, thyme and reserved salt pork to the pan and cook until heated through and the flavors are blended, about 5 minutes.

Dip the tips of the toast points in the parsley to coat. Serve with the parsley dipped croutes.