Preheat your oven to 350°F (175°C) and line an 8x8-inch baking pan with parchment paper.

In a large mixing bowl, whisk together flour, cocoa powder, powdered sugar, and salt until well combined.

In another bowl, cream together softened butter and vanilla extract until light and fluffy.

Combine the butter mixture with the dry ingredients using a spatula until a uniform dough forms.

Press the chocolate dough evenly into the prepared baking pan.

Bake for 20-25 minutes until edges are firm; center should be soft.

Sprinkle chocolate chips on top of the baked shortbread and let them melt before spreading them evenly.

Sprinkle sea salt flakes over the melted chocolate layer for added flavor.

Allow to cool at room temperature for 10 minutes before refrigerating to set completely.

Once set, lift out using the parchment paper and slice into bars.