2 oz of Gin
2 tsp of Light Cream
1 tsp of powdered sugar (or sugar)
carbonated water (or sparkling water)
1 of egg
1/2 of msr tequila (or Agavero Tequila Liqueur)
Shake all ingredients (except carbonated water) with ice and strain into a cocktail glass over two ice cubes. Fill with carbonated water, stir, and serve.