Wash the spinach and put it in a blender together with the water and blend until completely smooth.*
In a mixing bowl, add the flour, baking powder, salt, and sesame seeds. Stir to combine, then add in the spinach-water and olive oil. Stir to combine again, then mix and knead with your hands (or use a kitchen machine with a dough hook) until it's a smooth dough. Add more flour if your dough is too sticky.
On a lightly floured parchment paper, roll out the dough as thin and even as possible.
Cut it with a pizza cutter length- and widthwise. Carefully pull the parchment paper with the crackers onto a baking sheet.
Bake them in the oven for about 15-20 minutes (until they get crispy).
Let them cool off and enjoy!
*If your blender is having troubles getting the spinach into the blades, use double the amount of water and spinach and use only 1/2 cup of spinach water for the crackers. You can use the rest of the spinach water for a smoothie or of course, make another batch of spinach crackers.
Expert tip: Rolling out the dough as thin as possible is the most important step. Really take your time rolling out the dough as thin and evenly as possible. Otherwise, your crackers will end up too hard or chewy and unevenly baked.
The consistency of the dough: Flour, water, even altitude matter when making the dough, so it's best to trust your instincts a bit when making the dough. Add water until you can make a smooth dough. If you're not sure, it's best to make it too wet than too dry, you can always work more flour into the dough while rolling out the crackers. A wetter dough is easier to roll out than one that is hard and crumbly.
The cracker thickness: Roll out the dough as thin and as even as possible. This ensures even baking! If they are not thin enough, they will be rather chewy than crispy. The best way to do this is to roll out the dough on a lightly floured parchment paper, cut them, and then carefully pull the parchment paper with the crackers onto the baking sheet. It also helps if you take your time rolling out the dough..sometimes it looks like it doesn’t get any thinner. Then I walk away for one minute and come back..then the dough has relaxed a bit and can be rolled out easier and thinner.
Rolling pin: A proper rolling pin helps a lot with rolling the dough evenly. It works best with a large rolling pin with rotating handles.
Baking times: All ovens are different. Keep a close eye on them if you make them the first time. If a few of them start to puff up a bit, that's a good sign! They should get slightly golden/brown. If you're not sure, they should be crispy to the touch.