First grind pumpkin seeds in a blender. If you're making 25 bliss balls (as the recipe is written), put 100g of pumpkin seeds in a blender in two separate batches (2x 50g). This step is very important because it can make or break the recipe. Pumpkin seeds need to stay very dry as well as hemp seeds. Otherwise the bliss balls will become too wet and oily, it will not be possible to shape them into a ball nicely and the taste will also be affected. Transfer ground pumpkin seeds into a larger bowl.
Grind hemp seeds, again in two separate batches. Add them to the bowl with pumpkin seeds. Add also vanilla and cinnamon to these ground seeds. Mix together.
Grind dried mulberries in a blender. With mulberries there's no risk that they would become too wet so you can put them in a blender all at once. Make sure to grind them really well so that there aren't any whole parts of dried mulberries left.
Add all medjool dates into the blender without removing ground dried mulberries. Keeping dried mulberries in the blender will help with the stickiness of medjool dates as mulberries will add dryness to them. Mix and if there are still some larger parts of medjool dates in the blender, mix with a spoon and blend again.
Transfer the medjool date-mulberries mixture to the bowl. Mix together with your hand until you get a homogenous sand-like mixture. Don't squeeze medjool date-mulberries mixture too strongly by itself because you can end up with somewhat hard clumps in your energy balls. Instead incorporate dry mixture into the sticky mixture and separate sticky clumps that way.
Now add to the bowl sunflower seed butter, tahini and cold water. Mix together first with a spoon and then with your hand until you get a dough. Don't mix too strongly so that the dough doesn't get too dense.
Divide the dough in 25 equal parts (I weigh them in grams). Gently squeeze the dough so that it sticks together then shape the balls with your hands. Put them into a sealed box (so that they don't absorb the flavours from the fridge).
Store bliss balls in the refrigerator. If you wish you can take them out about 30 min before you want to eat them. They will get softer like this and they will be a little more pleasant to eat. You can take them with you on hiking trips as they keep their shape well outside the refrigerator.