1-1/2 ounces Partida Reposado Tequila
1-1/2 ounces fresh ruby red grapefruit juice
1/2 ounce Cointreau
1/2 ounce fresh squeezed lemon juice
1/2 ounce French cassis
Shake the first 4 ingredients in a shaker with ice. Strain into a chilled cocktail glass. Dribble the 1/2 French cassis down the inside of the glass so it will settle at the bottom.