Preheat oven to 350℉.
Line a baking tray with parchment paper and set aside.
In a small bowl, prepare your flax egg by combining ground flaxseeds with warm water. Set aside for 5 minutes.
To a medium-sized bowl, cream together softened vegan butter brown sugar and white sugar with a hand mixer until smooth and creamy.
Add in your prepared flax eggs, vanilla extract, salt, baking powder, baking soda, and flour and mix with a hand mixer until well combined.
Fold in chocolate chips with a spatula until evenly distributed in the cookie dough. Refrigerate for 1 hour.
Once dough has chilled, scoop with a cookie scooper (45 ml size, equal to 3 tbsp) and flatten the dough in one hand.
Use a small teaspoon to scoop your chocolate spread, then add it to the centre of the flattened cookie dough.
Begin to pinch the dough together, then roll the cookie into a ball and place on your lined baking tray. Ensure there is no chocolate coming out of the cookie.
Place cookies about 2.5 inches apart and bake for 14 minutes, or until cookies have flattened. It's okay if they look a little raw/soft, they will continue baking once removed from the oven.
Let cool for 10-15 minutes and optionally add flaky salt to top before enjoying.