Complex sentence: It is most commonly boiled and eaten as a leafy vegetable; the recommendation is to cook it in boiling water until the leaves soften, and to serve while some bite (crunch) remains (much like Samphire).
Split into simpler sentences: It is most commonly boiled and eaten as a leafy vegetable. Cook it in boiling water so the plant softens, but serve while some bite (crunch) remains (much like Samphire).