Shake all but sparkling wine, strain, serve up or on a rock, top with rosé.
The strawberry-infused tequila is called Tequila por mi amante, and is first cited in Charles H. Baker's Gentlemen's Companion. A recipe can be found here: bit.ly/dyEs1J Spanish speakers will note that "Tequila para mi amante" seems more likely to have been the original name than "por mi amante" ("for my lover," rather than "by my lover"), but it wouldn't be Baker if it weren't odd and confounding.
The original version of this drink called for half an ounce each of Lillet Rosé and rhubarb syrup instead of the St. Germain, a quarter ounce more lime, and no sparkling wine. I decided to update this drink to reflect what I think would be the more popular recipe and list the original here, rather than create two separate listings for very similar recipes.