There are a couple factors that contribute to ultra fudgy brownies! First, is using enough sugar paired with the addition of fat (oil, butter, egg yolks, etc). Sugar is hygroscopic, meaning it absorbs and holds liquid. This means that the sugar holds the oil, keeping the brownies moist the entire way through baking. u003cbr/u003eu003cbr/u003eSecond, is bake time. A perfect bake time is key to fudgy brownies. Over baking leads to cakey brownies rather than chewy brownies, so keep an eye on the time and don't be tempted to over bake.