04Fill each pan about three-quarters full with batter. Bake 20 to 25 minutes or until cake springs lightly when pressed with a finger. Flip cake out of pan onto paper towels or cake rack while still very warm.05When layers go into oven, start to make icing. Put a half-cup sugar in a large cast-iron pan and set over medium-high heat, stirring until sugar melts and begins to turn dark brown. Be careful not to let it burn. Remove pan from heat.06Add butter, cream, remaining sugar and salt. Over medium-high heat, bring to a boil and cook for three minutes, stirring, until it reaches about 240 degrees on a candy thermometer.07Remove from heat and add vanilla and baking soda. Using an electric hand mixer, beat until the icing is spreadable and fluffy. Frost tops of each layer immediately, stack and then frost sides of cake.