It is certainly easiest to use a food processor when making bliss balls, but you can make bliss balls by pulsing the dates, chia seeds, and peanut butter together in a Vitamix or similar high speed blender. You can also very finely dice the soaked dates and mix with chia seeds and peanut butter in a bowl with a wooden spatula. This method won't be as smooth as using a food processor, but it will stick together as long as you dice the dates small enough.