Recipe is here
The Smoothest, Creamiest, Best Liver Mousse Ever - Complete with Parsley and Fennel Frond Gelée
I've simplified Richard's recipe a bit and also halved it as this liver mousse doesn't keep very long. It's so rich that only 5-6 bites will satisfy you in one sitting. But if you're cooking for a crowd, by all means, use the full recipe by doubling what I'm giving you here. The full recipe makes approximately 1 quart of liver mousse which is enough as an appetizer for about 12 people.
Downloadable Instructions
To make 1/2 quart mousse, start off by getting some boiling water handy and deciding what serving vessel(s) you would like to use. I like to use my 16-ounce rectangular ceramic dish. You can use something similar or two 8-ounce ramekins. Whatever it is you choose, this will be your serving dish as the mousse is served in the same container in which it's baked; there's no unmolding involved. Metal is a bad idea. Glass is okay, though a bit strange to the eye. Ceramic, I think, is your best bet.
Once the issue of serving vessels is settled, find another pan big enough to fit your baking container(s) into and deep enough to hold hot water whose level is supposed to come half way up the sides of the serving container(s). If you've baked anything au bain marie before, you know the drill. Once that's done, preheat the oven to 300 degrees F.
Then saute one small onion and one clove of garlic, both finely chopped, in 1 tablespoon butter in a saucepan over medium heat. You just want to soften the onion and garlic, not caramelize them. Once the onion and garlic pieces are softened, add 1/4 cup of heavy cream to the pan, cover, and gently simmer 2-3 minutes until the onion is very soft.
Add 7 tablespoons of butter to the pan. When the butter has melted, remove the pan from heat and pour the content into the best blender you have (let's hope you get a high-speed blender like a Vitamix or K-Tec/Blendtec this holiday season, because they're awesome!). Add to the blender 1/2 pound of raw chicken liver, 1 teaspoon salt, 1/2 teaspoon freshly ground pepper. Blend until the mixture is smooth, scraping down the sides as necessary. (To be sure that your mousse is really, really smooth, I would take an extra step of straining your mousse mixture through a fine-meshed sieve once before baking it.)
Pour the liver mixture into the baking/serving vessel(s) of your choice. Tap the bottom(s) of the dish(es) lightly against the countertop to get rid of air bubbles. Then place the filled dish(es) inside the larger pan. Place the pan in the oven and carefully pour boiling water into the larger pan until the water is half way up the sides of the baking dish(es). Baking time will vary depending on whether you bake the whole thing in one big pan or divide it among smaller dishes. It takes about 20-25 minutes for the mousse to cook in my 16-ounce ceramic dish. So if you use smaller containers, I'd check for doneness after 10-15 minutes have elapsed. You know the liver mousse is done when the mousse is set around the edges and the center is only very slightly jiggly. Remove the baking dish(es) from the pan and let the mousse cool to room temperature.
In the meantime, make the gelée. Choose your favorite green leafy herbs or vegetable (parsley and fennel fronds are used here). Take about a handful of it and blend that with 1/4 cup of water, a squeeze of lime or lemon, a pinch of salt, and a pinch of sugar, until liquefied. Strain the mixture through a cheesecloth or coffee filter-lined sieve to get a completely clear, sediment-free green liquid. Whisk 1 teaspoon of unflavored gelatin powder into the herbal liquid and microwave it just to melt the gelatin. Do not allow the mixture to boil.
Arrange fresh herb leaves, shaved carrots, or whatever strikes your fancy on the top of the your mousse, then submerge and seal them in place by pouring the gelatin mixture over the entire surface of the mousse. Refrigerate the mousse for 4-6 hours. Refrain from touching the surface of the gelatin lest your fingerprints become evident for all party guests to see. Just let the thing set undisturbed.
The assembled mousse can be made and refrigerated up to 3 days in advance. For best result, let the mousse stand at room temperature for half an hour before serving.