Preheat the oven to 350°F (175°C) and line an 8x8 inch square baking pan with parchment paper, leaving an overhang on two sides.
In a medium mixing bowl, sift together the oat flour, cocoa powder, and sea salt to remove lumps and ensure even distribution.
In a separate large bowl, whisk the melted butter and granulated sugar together until the mixture is well combined and slightly grainy.
Add the eggs and vanilla extract to the sugar mixture, whisking vigorously for approximately 2 minutes until the batter becomes smooth, glossy, and slightly lightened in color.
Using a rubber spatula, fold the dry ingredients into the wet ingredients until no streaks of flour remain, being careful not to overmix.
Gently fold in the chocolate chips.
Transfer the batter into the prepared baking pan and smooth the top with a spatula.
Bake for 22 to 25 minutes. The brownies are done when a toothpick inserted into the center comes out with a few moist crumbs attached.
Remove from the oven and allow the brownies to cool completely in the pan for at least 30 minutes; this stage is critical for the oat flour structure to set properly before slicing.