You can soak the dates in warm water for 10 minutes to soften them. It makes it easier to blend but not necessary. Any nut mix will do. Just use what you have on hand and enjoy. Both the crust and filling will soften at room temperature so make sure to not keep it out too long. If you want to keep it longer, you can put it in the freezer a few days until ready to enjoy. You just need to take it out a few hours to soften before eating.