Preheat oven to 375°F (190°C). Prepare a large baking sheet with parchment paper and set aside.
In a medium bowl, stir the ground flax with 2 tablespoons of warm water and let sit for 5 minutes to thicken.
Add peanut butter, cane sugar and brown sugar and vanilla and mix with a fork until blended. Then, sprinkle over almond meal, baking powder and salt and work in thoroughly with a fork until mixture is thick and well-combined.
Scoop 1 tablespoon of dough and roll into a ball. Then flatten to ¼ inch (0.75cm) thick and 2 inches (5 cm) wide. Place 1 inch (2.5cm) apart on cookie sheet.
Bake for 8-10 minutes until cookies look cracked on top (it will settle as they cool!) and bottoms appear golden brown. Remove from heat and let cool for at least 10 minutes - or completely - before handling as they will firm as they cool up.
Store at room temperature, lightly covered, for 3-4 days. Cookies will freeze well.