Hydrate chia seeds in 1⁄2 cup of warm water for about 30 minutes until they turn into a thick gel. Combine all other ingredients in a bowl until well-mixed. Form into a 1⁄4 - 1⁄2 inch thick square on a piece of parchment paper on a baking sheet. Bake at 350F for 30 minutes, allow to cool for about 20 minutes and then cut into desired size.