Step 1Pour the vodka into a pint glass, add the one-half sliced blood orange and muddle it but not too much, about 6 times with a spoon. Add the Cointreau,
Step 2and chill in the freezer about 15 minutes, then remove from freezer and discard orangeslices.
Step 3Fill a cocktail shaker halfway with ice. Add the lime, lemon and orange juices and the drop of bitters. Shake hard for 8 seconds or until cloudy.
Step 4Strain into the pint glass with the chilled vodka mixture. Stir well (don't shake). Pour (don't strain) into a Martini glass. Float the remaining blood orange slice on top.