Preheat oven to 350 ° F (177 ° C). Line a large baking sheet with parchment paper and set aside.
Combine the ground flax and water in a small bowl. Set aside for 10 minutes. It will thicken and gel up (this creates a flax egg).
In a large bowl, add the flour, baking soda, salt, cinnamon and nutmeg. Whisk to combine.
In a medium bowl, cream the butter and sugar using a hand or stand mixer (medium-speed). *See note on how to do this by hand.
Mix in the flax egg and vanilla until just combined.
Now add the sugar and butter mixture to the large bowl of dry ingredients. Using a spatula, mix together until just combined and a dough is formed. Don't over mix. The dough will be slightly sticky and thick. If the dough is crumbly, add 1-2 tablespoons of vegan milk or water to help it stick.
Gently fold in the oats, chocolate chips, and raisins. I recommend chilling the dough for 15-20 minutes before continuing. If you chill longer than 30 minutes, let the dough sit out for 10 minutes before beginning.
Roll dough into 1 1/2 inch balls, (about 1.5 tablespoons) and place onto baking sheet about 2 inches apart. You can also use a Cookie Scoop. Slightly press them down, using a spoon or your hands. Place the remaining dough in the fridge until you're ready to make the 2nd batch.
Bake for 12-15 minutes or until the edges are lightly golden. Don't over bake. They will be soft and look undercooked on top and that's normal. Remove from the oven and let them cool on the baking sheets for 10 minutes. Transfer to a cooling rack. Make sure the baking sheet is completely cool before starting the second batch.