Prep. Preheat oven to 350ºF.
Prepare a 9 inches baking pan lined with parchment paper and leave a few inches of overhang on the sides so you can easily remove the brownies later.
Melt the chocolate using the double boiler method. Heat up a small saucepot with a few inches of water in it. When it starts to simmer, place a heatproof bowl over the top with olive oil and chocolate chips. Stir constantly until about 70-80 percent of the chocolate chips are melted. Take the bowl off the pot and continue stirring until all the chips are melted and the texture smooth.
In a medium mixing bowl beat the eggs for 2-3 minutes until bubbly.
Pour in the melted chocolate mixture and mix on low until smooth. Add vanilla and sugar. Mix on low.
In a separate mixing bowl add all the dry ingredients (GF flour, cornstarch, salt, cocoa powder). Whisk until just combined. Add the this to the wet ingredients bowl and gently combine with a spatula until the batter becomes thick and smooth.
Pour the brownie batter into a prepared baking dish, even out with a spatula as much as you can (the batter will be sticky!) and bake for 20-25 minutes. Insert a toothpick in the center and if it comes out slightly moist and with crumbs you’re good to go. The center should still be very moist. When ready, remove from oven and let cool for 15 minutes in the pan, then gently remove and let cool completely on a wire rack. For easier and even cutting, place the brownies in the fridge for at least 30 minutes.
Remove from the fridge and cut the batter in half. Make a zig-zag cut on both sides creating 3 triangles on each.
Gently slide the triangles out and trim the edges where needed. Eat the leftovers!
Decorate. With powdered sugar: mix about 4-5 tablespoons of powdered sugar with a teaspoon of milk added gradually. Whisk and add more milk/powdered sugar until you reach the desired thick consistency.
Add food coloring now. Place the thick mixture into a pastry piping bag or a zip lock bag, cut out a very small tip of one corner and decorate the brownies!
With chocolate: Melt the white chocolate the same way you did with semi-sweet chocolate chips but without oil. You can add a little oil (about 1 teaspoon) if needed for a smoother consistency. If using food coloring, add it now.
Place the chocolate in a pastry piping bag or a heatproof bag and use the smallest round tip you have (or just cut out a small piece from the corner of the heatproof bag). Drizzle over each brownie triangle and immediately add the sprinkles.
Let those Christmas Brownies set and serve immediately!