This prompt is interesting to me because it is actually quite difficult. While Passover has the usual blessings for a holiday (on candles, wine, handwashing, bread or Matzah in this case, the Shehechiyanu for a new experience), I can’t, offhand, think of any particular blessing that is special to Passover. The entire holiday is one big blessing, if you will, of thanksgiving for our redemption from Egypt.
There is one interesting point relating to blessings that happens during the Seder. Observant Jews always wash their hands with a blessing before eating any meal that includes bread, and we definitely do that before the meal at the Seder. However, as part of all the odd goings-on in the first part of the Seder, we wash our hands without a blessing before eating the karpas, or green vegetable. One purpose of this aberrant behaviour is to confuse the children and tempt them into asking questions.
I think that is what I really want to celebrate about Judaism today – the encouragement of questioning, thinking and probing. Why do we do this? Why do we not do that? What is the purpose of keeping kosher, keeping Shabbat or any of the other commandments that make us separate and different from all other nations?
Judaism has its share of zealots, and certainly has a reputation for being a very rule-based lifestyle that would not appear to encourage questioning. Many of the most externally observant communities have very strong social control structures, designed to keep the believers in line and stifle dissent. But even in the very heart of this apparent conformity, a spark of questioning springs up and is encouraged, at least within a certain setting.
I believe that to be the true blessing of Passover. Never stop questioning.