Preheat your oven to 350 degrees Fahrenheit and line a 13” x 9” baking pan with parchment paper. You can also spray the pan with cooking spray or grease it with butter.
In a large mixing bowl, combine the melted unsalted butter, avocado oil, granulated cane sugar, light brown sugar, and vanilla extract. Mix these ingredients until they are well combined. The mixture will have a glossy, greasy appearance, and that’s perfectly normal!
In a separate small bowl, whisk the eggs together until well-beaten. Then, transfer the beaten eggs to the bowl with the butter-sugar mix. Stir until everything is well integrated.
In another bowl, sift together the gluten-free all-purpose flour, cocoa powder, instant coffee, and sea salt. This step helps break up any clumps and ensures even distribution of dry ingredients.
Gradually pour the dry ingredients into the wet mixture. Stir gently until a thick batter forms. Be careful not to overmix; a few lumps are perfectly fine.
Next, fold in the semi-sweet chocolate chips or chopped chocolate bars until evenly distributed throughout the batter.
Pour the brownie batter into the prepared pan, spreading it out evenly with a spatula. Make sure it reaches the corners of the pan for consistent baking.
Place the pan in the center of the preheated oven. Bake for 25 to 30 minutes for fudgy brownies, or 35 to 40 minutes for firmer brownies. If you like your brownies gooey, aim for around 23 to 25 minutes. They should have a slight jiggle in the center when done.
After baking, let the brownies cool in the pan for about 15 minutes. This cooling period allows them to set before slicing. Once cooled, cut into squares and serve warm or at room temperature. Enjoy!