1 tsp orange marmalade
35ml Tequila
15ml Triple Sec

Add the marmalade and tequila to a cocktail shaker.
Stir to dissolve
Add the Triple Sec and a scoop of ice
Shake vigorously for at least 20 seconds
Run a cut lime around the rim of a margarita glass
Dip the rim in salt
Strain the cocktail into the salt rimmed glass 
Garnish with a slice of fresh lime