Bring 4 litres of water to the boil, add salt and lemon half.
Remove outside leaves and stem from the artichoke and discard. Using a spoon, remove the choke (fibrous inner centre) and discard.
Add artichokes to saucepan and simmer for 30 minutes. Drain.
Meanwhile, simmer vinegar, wine and peppercorns until reduced to 2 tablespoons. Strain, discarding peppercorns, and pour liquid into a stainless steel bowl.
Add yolks and water to the bowl and place over a pot of gently simmering water. Whisk for about 7 minutes, until creamy.
Slowly add hot clarified butter, continuing to whisk until thick. Stir in lemon juice and remove from heat. Season to taste with salt and white pepper and cover with plastic wrap. Place in a warm place until required.
Fill centre of artichoke with crabmeat and place in a steamer. Steam for 10 minutes.
Serve crab-filled artichokes warm, seasoned with salt and cracked black pepper and drizzled with hollandaise.