Root Beer Float Cake with vanilla ice cream frosting Recipe

Ingredients

• 2 ½ cups root beer (such as Sioux City), divided
• 1 ½ cups packed light brown sugar, divided
• 2 ¼ cups all-purpose flour
• 2 tsp. baking powder
• ½ tsp. each table salt and freshly grated nutmeg
• ¼ tsp. each ground cinnamon and baking soda
• ⅛ tsp. ground star anise (optional)
• ⅔ cup vegetable oil
• ½ cup sour cream
• ¼ cup molasses
• 3 eggs
• 1 Tbsp. pure vanilla extract
• 1 Tbsp. root beer concentrate (such as Zatarain’s)
• ½ cup root beer
• 2 Tbsp. granulated sugar
• 1 tsp. root beer concentrate
• 1 cup melted vanilla ice cream
• ¼ cup all-purpose flour
• 2 sticks unsalted butter, softened (16 Tbsp.)
• ¾ cup granulated sugar
• ½ tsp. table salt
• 1 Tbsp. vanilla bean paste