Perfect steak with sauce Bernaise

• 2 beef fillet steaks (3-6 cm thickness)
  或 beef rump steak (3-6 cm thickness)
• sea salt to season
• ground black pepper to season
• olive oil to drizzle

Bernaise sauce

• 4 - 5 sprigs fresh tarragon leaves only; stalks reserved
• 80 g eschalots
• 80 g white wine vinegar
• 180 g unsalted butter cut into pieces
• 4 egg yolks
• ½ - 1 tsp salt
• 2 pinches ground black pepper