Sprinkle lamb with salt and pepper; dredge in 1/4 cup flour. Place lamb, fat side up, in a large Dutch oven. Add 1 1/2 cups boiling water. Cover and bake at 350° for 1 1/2 hours or until lamb is tender, basting occasionally with pan liquid. Transfer lamb to a warm serving platter, reserving pan liquid; keep warm.
Dissolve bouillon cube in remaining 1 cup water in a small mixing bowl; add chopped mint, vinegar, and reserved pan liquid, mixing well. Set aside.
Melt butter in a saucepan; cook until golden brown. Add remaining 1/4 cup flour, stirring until smooth. Cook over medium heat 1 minute, stirring constantly. Gradually add mint mixture. Cook over medium heat, stirring constantly, until thickened and bubbly. Strain. Serve sauce with lamb. Garnish with fresh mint leaves, if desired.
Oxmoor House Homestyle Recipes