There are several desserts including some "dried fruit treats" that require no cooking. The date-nut pinwheel cookies would work well for an event since you can make the refrigerator dough weeks in advance.
My husband is going to be away this weekend to attend the bar mitzvah of the younger son of a friend of his from high school in New Jersey. I was happy when my son and I were invited by minyan friends to their house for Shabbat dinner and I volunteered to bring grape juice and fruits and nuts and haggadot for a (brief) Tu Bishvat seder. Also invited to dinner was a family from my minyan that had recently moved to a house just a few blocks from my house. I had meant to invite them for Shabbat, but been too tied up with other things to manage it.
But then I got the flu earlier this week. On Monday, I hurt so much all over and was so weak that I really couldn't get out of bed. I had hoped that I would recover quickly, but I have continued upper respiratory problems with a bad cough. I'm also tired and my back hurts because I have to sleep propped up with extra pillows and I keep coughing myself awake at night. I checked Internet sources on flu transmission and found that I could still be contagious through this weekend. So sadly, I cancelled out of the dinner and will also miss the special kiddush to welcome "new members" on Saturday with a brief Tu BiShvat seder put together by a member who runs a recycling business so this holiday is very near and dear to his heart. (I worry that it could even be fatal if one of the older physically frailer members caught my flu from me---one member recently celebrated her 100th birthday.)
But so as not to miss the holiday altogether, I took the time while my son was in his double bass lesson (although I usually sit in the room and work on my laptop) to dash over to the kosher supermarket and buy some nice food for Shabbat as well as fruit and nuts of the right categories and red grape juice (we have plenty of white at home). I tried to make sure that I didn't cough in the direction of the cashier and hope she didn't pick up germs from touching the same items I touched.
I hope my son will humor me and read the haggadah with me and think about the themes as we eat the fruits and nuts. I bought some kumquats even though they were probably expensive (I didn't even check the price) and some of the fruits looked unripe, because they are one of the few fruits that comes from a tree that can be eaten completely with no outer shell or pits to discard, and I don't think my son has tasted one before. We'll get to do a Shehecheyanu since it will be new to both of us since Rosh Hashana. The hagaddah lists for other fruits in that category grapes and berries, but those fruits come from vines or bushes, not trees. (Oh, I forgot: I also bought dried figs which are eaten in their entirety, but I like to have a fresh fruit for each category.)
wow that's beautiful! Our community seder is tomorrow night, and for once, I am NOT the principle planner! I am just showing up with pink wine, pink juice, and a bunch of dried figs. Looking forward to it!