A fine recipe for lemon curd is at http://www.joyofbaking.com/LemonCurd.html.
The ingredients are very simple: lemon, and curd.
An alternative recipe involves eggs, juice, zest, butter and sugar.
Little lemon-related tippettes included are that room temperature lemons produce more juice, and refrigerated lemons are easier to ‘zest’/’dezest’: the zest is easier to remove from cold, firm lemons. So now you know.
The Google omnipotitentometer finds ‘about 549,000’ web pages featuring lemon curd. The Lemon Curd Foundation are planning a big publicity push and are saving up for a large firework display to celebrate “the Billionth Lemon Curd Website,” which may take a few more lemony years.