1. Heat-Treat the Flour (Crucial Step!):
* Preheat your oven to 350°F (175°C).
* Spread the flour evenly on a baking sheet.
* Bake for 5-7 minutes. The flour should not brown, but it needs to reach an internal temperature of 165°F (74°C) to be safe. Use a food thermometer to check if possible.
* Remove from oven and let it cool completely. Sift it afterwards to remove any clumps that may have formed.

2. Prepare the Pan:
* Line an 8×8 inch (20×20 cm) square baking pan with parchment paper, leaving an overhang on two sides. This will make it easy to lift the bars out later.

3. Cream the Butter and Sugars:
* In a large mixing bowl, using an electric hand mixer or a stand mixer fitted with the paddle attachment, cream together the softened vegan butter, light brown sugar, and granulated sugar.
* Beat on medium speed for 2-3 minutes until the mixture is light, fluffy, and well combined.

4. Add Wet Ingredients:
* Beat in the plant-based milk and pure vanilla extract until just combined. Scrape down the sides of the bowl as needed.

5. Incorporate Dry Ingredients:
* Add the cooled, heat-treated flour and salt to the wet ingredients.
* Mix on low speed until just combined. Be careful not to overmix, as this can make the bars tough. The dough will be thick.

6. Fold in Chocolate Chips:
* Gently fold in the 1 cup of vegan chocolate chips using a spatula until they are evenly distributed throughout the cookie dough.

7. Press Dough into Pan:
* Transfer the cookie dough mixture to the prepared baking pan.
* Using the back of a spoon, an offset spatula, or your clean hands (lightly moistened if the dough is sticky), press the dough evenly into the bottom of the pan. Aim for a smooth, level surface.

8. Prepare the Chocolate Topping:
* In a microwave-safe bowl, combine the 1 cup of vegan chocolate chips for the topping and the 1 tablespoon of coconut oil.
* Microwave in 20-30 second intervals, stirring well after each interval, until the chocolate is smooth and completely melted. Be careful not to overheat or burn the chocolate.
* Alternatively, you can melt the chocolate and coconut oil in a heatproof bowl set over a saucepan of simmering water (double boiler method).

9. Pour Topping Over Dough:
* Pour the melted chocolate mixture evenly over the cookie dough base in the pan.
* Use an offset spatula or the back of a spoon to spread the chocolate into a smooth, even layer, covering the entire surface.

10. Chill to Set:
* Carefully transfer the pan to the refrigerator.
* Chill for at least 2 hours, or until the chocolate topping is firm and the cookie dough base has firmed up. For a quicker set, you can place it in the freezer for about 45-60 minutes.

11. Slice and Serve:
* Once chilled and firm, use the parchment paper overhangs to lift the entire block of cookie dough bars out of the pan and onto a cutting board.
* Using a sharp knife (run it under hot water and wipe dry for cleaner cuts), slice into 16 squares (4×4 grid) or desired shapes/sizes.
* Serve immediately or store as directed below.