Halve the lemon and squeeze the juice into a large bowl of cold water.
Snap off the outer leaves of the first three or four outer layers of leave from bottom of an artichoke. Use a serrated knife to cut off the stem at the base and the top half of each artichoke.
Using a small spoon or melon baller, scrape out the choke and any sharp leaves from the centre of the artichoke.
Repeat Steps 2 & 3 for all the artichokes
Drop the cleaned artichokes into the acidulated water as soon as they are trimmed.
Tip the lemon water into the bottom of steamer. Add the artichokes to the steamer basket and set over a high heat for around 15 minutes or until the bottom of the artichoke can be easily pierced with a skewer.
Meantime, warm your bearnaise sauce over a water bath, whisking every now and again to keep the bearnaise as emulified as possible. Do not worry if it splits, we are aiming for flavoured butter not a perfect sauce with this recipe!
When the artichokes are steamed, pour the bearnaise butter over. Top with a poached egg if using.