Combine strawberries, sugar and ¾ cup water in a small saucepan over medium-high heat. Bring to a boil, stirring occasionally. Reduce heat to a simmer and cook until mixture has thickened slightly and reduced a little, about 10 minutes.
Strain strawberry mixture into a jar and discard solids. Let cool completely and refrigerate until ready to use.
Pour 1 ¾ cups vodka from bottle and reserve for another use. To the remaining vodka, add ½ cup cooled strawberry simple syrup, orange liqueur, lime juice, and remaining ¼ cup water. Seal the bottle and tilt it gently to mix the ingredients.
Place bottle in freezer for at least 6 hours or until ready to serve.
Lightly shake bottle before serving in a martini glass and garnish individual cosmos with a slice of lime if desired.
