Store-bought preserves and chocolate spreads are great—my favorite is raspberry preserves and chocolate hazelnut spread. Use as many different fillings as you like. You can make this dough a day ahead. After punching it down and transferring to the fridge, leave it to chill overnight. The next day, continue as instructed. Do not fill the sufganiyot until they’re fully cooled to room temperature, or else the filling will squirt back out at you.