How to Make It
Preheat oven to 350. Using a stand mixer or hand mixer, cream together the peanut butter, butter, and sugar, until the peanut butter starts to become fluffy, about 3 minutes. Add the egg and vanilla, and mix on medium speed until all of the ingredients are combined, about 2 minutes.
In a separate bowl, sift together the flour, baking soda, and flax seed meal. Slowly add it to the butter mixture, and beat it only enough to combine all of the ingredients. Add the walnuts, chocolate chips, and flax seeds, and mix by hand to incorporate.
Prepare a baking sheet with a non-stick baking mat or parchment paper. Scoop out heaping tablespoons of cookie dough, and gently form each one into a ball, and place them 2 inches apart on the baking sheet. Lightly press down on the center of each with the back of a fork, and repeat creating a grid on top of the dough.
Bake, uncovered, until golden brown, about 18 to 20 minutes, rotating the sheet halfway through to ensure evenly baked cookies. Let the cookies cool on the baking sheet for 3 to 5 minutes before transferring to a wire rack or towel to cool. If using only one baking sheet, repeat step 4 until you’ve gone through all of the dough.
These peanut butter chocolate chip cookies call for flax seed meal, but because store-bought flax seed meal lacks the nutritional value of whole flax seeds, it's best to make a fresh, coarse-ground flax seed meal just before you use it. It's easy to make with a with a food processor, clean coffee grinder, or blender. One cup of whole flax seeds yield about 1 2/3 cups of flax seed meal, so leave room for expansion (use any leftover flax seed meal in smoothies or sprinkled on top of cereal or yogurt).