Parsnip Cake with Blood Orange Buttercream

Name: Parsnip Cake with Blood Orange Buttercream
Ingredients: For the blood orange buttercream:; 2 blood oranges, juiced (about 1/2 cup juice); 2 sticks (8 oz) butter, at room temperature; 4 cups confectioners’ sugar; For the cake:; 3 eggs; 1 cup sugar; 1/2 cup neutral oil; 1/2 cup milk; 1 teaspoon kosher salt; 1/2 teaspoon vanilla extract; 1 1/2 cups all-purpose flour; 2 teaspoons baking powder; 1 teaspoon ground cinnamon; 1/4 teaspoon grated nutmeg; 1/4 teaspoon ground allspice; 1/4 teaspoon ground cloves; 2 cups grated parsnips (from 1 pound peeled parsnips); 1 teaspoon grated fresh ginger or 1/2 teaspoon ground ginger