Preparation Toss Brussels sprouts with 1/4 teaspoon salt and steam on a rack over boiling water, covered, until just tender, 4 to 5 minutes. Transfer to a warm plate. Meanwhile, pat fish dry and season with 1/2 teaspoon salt and 1/4 teaspoon pepper. Dredge in flour, knocking off excess. Heat oil and 1 tablespoon butter in a 12-inch heavy skillet over medium-high heat until foam subsides. Cook fish, turning once, until browned and just cooked through, 2 1/2 to 3 minutes total. Add fish to plate with Brussels sprouts. Discard fat from skillet and reduce heat to medium-low. Add almonds and remaining 2 tablespoons butter and cook, stirring, until almonds and butter are golden brown, 1 to 2 minutes. Remove from heat and stir in lemon juice. Season with salt and pepper. Pour sauce over fish and Brussels sprouts.
Preparation Toss Brussels sprouts with 1/4 teaspoon salt and steam on a rack over boiling water, covered, until just tender, 4 to 5 minutes. Transfer to a warm plate. Meanwhile, pat fish dry and season with 1/2 teaspoon salt and 1/4 teaspoon pepper. Dredge in flour, knocking off excess. Heat oil and 1 tablespoon butter in a 12-inch heavy skillet over medium-high heat until foam subsides. Cook fish, turning once, until browned and just cooked through, 2 1/2 to 3 minutes total. Add fish to plate with Brussels sprouts. Discard fat from skillet and reduce heat to medium-low. Add almonds and remaining 2 tablespoons butter and cook, stirring, until almonds and butter are golden brown, 1 to 2 minutes. Remove from heat and stir in lemon juice. Season with salt and pepper. Pour sauce over fish and Brussels sprouts.