Fresh Whiskey Sours are made from just-squeezed lemon and orange juice. Each glass is rimmed with a sugar halo and garnished with a fresh orange slice.
Prepare 4 glasses: Place 1/4 cup orange juice in a shallow dish. Fill another shallow dish 1/2-inch deep with sanding sugar. Dip rims of glasses into juice and then into sugar. Chill in refrigerator 10 minutes.
Place remaining 1 cup orange juice, sugar, lemon juice, and bourbon in a blender. Fill blender to top with ice. Blend until smooth, and transfer to prepared glasses. Garnish with orange or lemon slices.