How to Make It
Melt butter in a small heavy saucepan over medium; skim white milk solids from surface, and discard. Add hazelnuts to pan; cook, stirring occasionally, until butter and nuts begin to brown, about 5 minutes. Remove from heat, and keep warm.
Heat 1 1/2 tablespoons olive oil in a large skillet over medium-high. Add half of the crabs to skillet; cook until browned and done, about 2 minutes on each side. Transfer cooked crabs to a platter, and sprinkle with 1/4 teaspoon salt. Repeat with remaining 1 1/2 tablespoons oil, half of crabs, and 1/4 teaspoon salt. Drizzle with warm butter and nut mixture. Serve with lemon wedges.