Preheat oven to 350°F.
Make the panko crust: melt the 1/4 cup pure butter (or coconut oil) in a small saucepan or microwave. In a medium bowl, combine 2 cups panko and 1/4 cup coconut sugar. Add the melted 1/4 cup butter (or coconut oil) and stir until the crumbs are evenly moistened.
Reserve 1/2 cup of the crumb mixture in a small bowl for the topping. Press the remaining crumb mixture firmly into the bottom and up the sides of an 8-inch pie plate. Set the prepared crust aside.
Make the brownie filling: in a small pot over low heat, melt the 1/2 cup pure butter (or coconut oil). Stir in 1 cup coconut sugar and continue cooking on low until the sugar has dissolved. Remove the pot from heat and let it cool for about 30 seconds.
Off the heat, stir in 2 teaspoons vanilla extract, then whisk in the 2 large eggs (lightly whipped) slowly until the mixture is smooth and homogenous.
In a separate bowl, whisk together 1/2 cup flour, 1/2 cup cocoa powder, and 1/4 teaspoon sea salt. Add these dry ingredients to the butter-sugar-egg mixture and stir just until combined. Add 1 cup chocolate chips and gently fold them in.
Pour the brownie mixture into the prepared panko crust. Evenly sprinkle the reserved 1/2 cup crumb mixture over the top.
Bake at 350°F for 25 minutes. Remove from the oven and cool completely on a wire rack before slicing.