How to Make It
In a small saucepan, cook the butter over moderate heat, stirring, until golden brown and nutty smelling, about 5 minutes. Add the shallot and garlic and cook over very low heat until the shallot is very soft, about 20 minutes. Remove from the heat.
In a small skillet, heat 1/2 tablespoon of the infused brown butter. Add the almonds and cook over moderate heat, stirring, until golden, 3 to 5 minutes. Transfer to a small bowl and season lightly with salt.
In a very large cast-iron skillet, heat 2 tablespoons of the brown butter. Add the brussels sprouts cut side down and season lightly with salt. Cook over moderately high heat until browned on the bottom, 3 to 5 minutes. Add 1/2 cup of water, cover and cook over moderate heat, stirring occasionally, until just tender and the water is evaporated, 5 to 7 minutes. Remove from the heat and stir in the lemon juice, fish sauce and the remaining brown butter. Transfer to a platter and top with the clementine sections, shiso, parsley, chives and almonds. Serve right away.