Put the ground flaxseed and water into a large-sized bowl; this will create a "flax egg." Set it aside while you prepare the dry ingredients
Put all of the dry ingredients into a separate medium-sized bowl and stir well.
Add the vegan butter, maple syrup, and vanilla to the large bowl with the flax egg. Using the back of a fork, mash the butter into the wet ingredients. Add the walnuts and chocolate chips; stir together.
Fold the dry ingredients into the wet ingredients.
Cover a flat baking sheet with parchment paper.
Measure a heaping Tablespoon of the batter and spoon it onto the cookie sheet. Repeat until all of the batter is used up. Space the cookies on the baking sheet 1 inch apart.
Bake for 20 minutes or until golden brown. When done, slide the parchment/cookies from the baking sheet onto the counter and let them cool before serving.
I always mix walnuts, chocolate chips, raisins, and the like with wet ingredients first. If directly added to the dry ingredients, flour can become stuck in the groves.