Preheat your oven to 350°F. While it heats, grease a 9x13 inch baking dish (or 8x8 for thicker brownies) with butter or cooking spray, making sure to coat the bottom and all sides evenly. This prevents sticking and ensures clean edges when you cut the finished brownies.

In a medium bowl, whisk together the gluten-free flour, salt, baking powder, and cocoa powder. Whisk thoroughly for about 30 seconds to ensure the leavening and cocoa are evenly distributed throughout the flour—this is crucial for gluten-free baking to achieve proper structure and consistent texture. Set this dry mixture aside.

In a large bowl, melt the butter over low heat or let it soften to room temperature, then add the room-temperature eggs one at a time, stirring well after each addition. Pour in the vanilla extract, then add both sugars and the red food color, stirring until everything is well combined and the color is evenly distributed throughout the batter. I like to use Kerrygold unsalted butter here because it adds a subtle richness that complements the chocolate and red velvet flavor beautifully.

Add the dry ingredient mixture from Step 2 to the wet mixture, stirring just until combined—don't overmix. Pour in the water and stir until the batter is smooth and no dry streaks remain. The water adds moisture to compensate for the gluten-free flour's tendency to absorb liquid differently, creating that fudgy texture we're after. I find that packing the brown sugar firmly gives the brownies an extra-moist, fudgier crumb.

Pour the batter into your prepared pan from Step 1, spreading it evenly into all corners with a spatula. Bake at 350°F for 30–35 minutes, until a toothpick inserted into the center comes out with a few moist crumbs—you don't want it completely clean, as that means overbaked brownies. The edges should look set while the center may still look slightly underdone; it will continue to cook as it cools.

Remove the brownies from the oven and let them cool in the pan for at least 15–20 minutes before cutting. This cooling time allows the structure to set properly, making them easier to slice cleanly. Cut into squares and serve at room temperature or slightly warm for the best texture and flavor.