Place the ice cubes in a cocktail shaker. 

Pour the vodka, schnapps, cider, and Vintage Original Seltzer over the ice and cover.

Shake until outside of shaker has frosted. Make sure to pause and slowly let the carbonated air out of the shaker once or twice during the shaking process and before you pour. 

Strain into a martini glass, and garnish with apple slice.

Source: Allrecipes.com