[header] How to make brownie christmas trees [title] Preheat the oven and prepare your baking pan. [step] Turn on the oven to 350 degrees f (176 c). Get out a rimmed half-sheet pan that measures 13x18-inches (33 x 45 cm). 
It should be about 1-inch deep. Spray the pan with baking spray or butter and flour the pan so the brownies won't stick.