In a small sauce pan, bring the rosé to a simmer.
Reduce the wine to half (1/2 cup or 100ml to 125ml). This should take 20 to 25 minutes.
Place the wine concentrate into a heat resistant container and chill it in the freezer until cool (approximately 15 minutes).
Add the wine concentrate and continue to beat on low speed until all of the ingredients are fully incorporated.
Increase the mixing speed to high and beat the buttercream for 5 to 10 minutes or until the buttercream is smooth and white in color.
Add 2 to 3 drops of rose pink food coloring and mix until the buttercream is pink.