Season the fish with cracked pepper.

In a small bowl, blend together the lemon juice, zest and 2 tablespoons of butter.

Spread over both sides of the fish.

Melt remaining butter in a nonstick frying pan over moderate heat.

Add the fish and cook for 2 to 3 minutes on each side, basting until tender and golden, flaking easily with a fork.

Portion the already steamed asparagus onto serving plates, top with the fish and drizzle with the yummy lemon butter in the pan.