Zest and juice the lemon, you will need 1 tsp zest and 2 tbsp juice.  Finely dice the olives then add the butter (softened to room temperature) - mix with a fork to combine.  Add the zest and juice to the butter mixture then season with salt and freshly ground black pepper to your taste preference blending until fully incorporated.  Heat the oil in a skillet over medium-high heat.  Add the broccoli and saute until softened; about 5-6 minutes.Season fish with salt and pepper. Grill or broil until white and firm to the touch; about 3-4 minutes per side. Transfer to plates with broccoli, and serve topped with 1/4 of the olive butter.