The Seder step involving hand washing with a blessing is Rachtzah.
Rachtzah is the sixth stage of the traditional 15-step Passover Seder. Participants wash their hands before the blessings over matzah and the eating of matzah. Unlike the earlier washing at Urchatz, this second washing is generally accompanied by the blessing for ritual hand washing.
The sequence reflects Jewish rules surrounding bread: Motzi, the blessing over bread, follows Rachtzah, and Matzah, the blessing specifically connected with eating matzah, follows Motzi. The arrangement makes the hand washing a preparation for the central food ritual of the Seder.
The most common confusion is between Rachtzah and Urchatz. Urchatz occurs near the beginning of the Seder, before Karpas, and normally has no blessing. Rachtzah occurs after Maggid and before the matzah blessings. Customs can vary among Jewish communities, but this distinction is the standard Seder structure.