Generally, yes: We recommend letting eggs for sweets like brownies or cakes/cupcakes come to room temperature for an hour or two before mixing them into the batter. A room temperature egg will "shock" the batter less and incorporate more evenly, keeping the temperature more consistent and resulting in a taller, more even rise (see this in action in our post on making the best homemade cupcakes!) That said, the impact in this particular recipe is pretty negligible: In our testing, the small batch brownies baked with a room temperature egg rose just slightly more than the brownies baked with a cold egg, and we couldn't tell a difference in a blind taste test. If you have the time and the inclination, go ahead and let your egg come to room temp on the counter before making this recipe (just like you would in other desserts, like cakes or cupcakes). But if you don't have time to bring the egg to room temperature here, don't worry about it — the brownies will turn out just fine!