Preheat oven to 325°F (160°C).
In a large mixing bowl, mix all ingredients together. Allow mixture to sit and thicken, around 10 minutes. (There shouldn’t be water left in the bowl, it should all be absorbed.)
Spread mixture onto a baking sheet, lined with parchment and lightly sprayed. Put another sheet of parchment on top and use your hands to flatten, around ⅛-inch thick.
Remove top sheet and sprinkle with salt, if desired.
Bake for 15-20 minutes, until golden brown around the edges.
Remove from oven, put a sheet of parchment on top, and flip it over onto another baking sheet. Remove bottom sheet of parchment (that was just in the oven) and use a pastry cutter to score square shapes into the cracker sheet.
Return to oven and bake 20-25 more minutes.
Allow to cool on baking sheet. Break apart with hands and enjoy!
Yields ~24 oat and seed crackers.