Preheat oven to 350 degrees F.
Line a 9x5 loaf pan with tin foil or parchment paper. In a cup or small bowl, mix ground flaxseeds with water to create flax “eggs." Let sit for a minute.
Add the flax “eggs” to a food processor along with all other ingredients except for the oat flour (or spelt), oats and raisins.
Process for a few minutes until a smooth mixture is formed. The mixture should have a pudding-like consistency and be somewhat thick.
Pour this mixture into a large bowl and mix in the oat flour (or spelt), whole oats, and dark chocolate chips or raisins, mixing all ingredients in evenly.
Separate the dough into two equal parts and scoop each one into a parchment-lined loaf pan and top with additional dark chocolate chips or raisins, if desired.
Bake for 40-45 minutes or until you can stick a fork or toothpick in the center and it comes out clean.
Remove the pan from the oven and let the bread set for at least 20 minutes before transferring to a plate to cool. Let cool completely before slicing, preferably for several hours, otherwise it will be sticky/crumbly when slicing.