Preheat your oven to 350°F. Prepare a 9x9-inch baking pan by greasing it and lining it with parchment paper.

In a medium-sized bowl, mix together the gluten-free flour, cocoa powder, and sea salt until evenly combined. Set this mixture aside for later use.

Using a double boiler or microwave, gently melt the chopped semisweet chocolate and coconut oil together. Stir until smooth and let the mixture cool slightly.

In another bowl, beat the sugar, eggs, and vanilla extract until the mixture is smooth and well blended. Gradually pour this into the slightly cooled chocolate and coconut oil mixture, whisking until fully incorporated.

Slowly add the dry flour mixture to the wet ingredients, folding gently until just combined. If you are using chocolate chips, fold them into the batter at this stage.

Transfer the batter into your prepared baking pan, spreading it evenly to ensure a smooth surface.

Bake the brownies in the preheated oven for 20 to 25 minutes, or until a toothpick inserted in the center comes out mostly clean for a gooey texture. If you prefer a drier brownie, bake for an additional 5 to 10 minutes.

Allow the brownies to cool completely in the pan before cutting them into squares. For storage, place them in an airtight container and keep them at room temperature for up to 3 days.