Bake Strawberry Rosé Cupcakes: tender rosé-infused cupcakes filled with jammy strawberry filling and silky buttercream.
Preheat the oven to 350°F and line a cupcake pan with white paper liners so everything is ready when the batter is finished. In a large mixing bowl, whisk together the granulated sugar, vegetable oil, whole eggs, and vanilla extract until the mixture looks glossy and slightly aerated. Add the sour cream (or Greek yogurt) and beat again until the batter is smooth and cohesive — it should feel silky and slightly thick against the whisk, not runny.
Sift the all-purpose flour with the baking powder and salt, then add the dry mix to the wet ingredients. With the mixer running on low, slowly stream in the sparkling rosé, followed by the milk, until the batter is homogenous and soft pale in color. Give the bowl one last gentle fold by hand to ensure no streaks of flour remain. Using a large cookie scoop, portion the batter into the lined cups, filling each about two-thirds full — the batter should hold its shape but still look silky and moist on the scoop.

Bake the cupcakes at 350°F for 14–16 minutes until a toothpick inserted in the center comes out clean. Remove the tray and allow the cupcakes to cool completely on a rack — they should settle to a light golden top and the crumb should feel tender and springy when pressed gently.
Combine the chopped strawberries with the granulated sugar, the tablespoon of flour, and the lemon juice in a saucepan and bring to a boil over medium-high heat, stirring frequently. Once the fruit breaks down and the mixture bubbles, reduce the heat and simmer until it thickens into a glossy, jammy sauce. Remove from heat and chill thoroughly in the refrigerator so the filling firms up and becomes spoonable.
When both cupcakes and filling are cold, cut or core a small cone from the center of each cupcake and gently spoon or pipe the chilled strawberry-rosé filling into the cavity. Press the removed crumb back on top lightly if desired, leaving a flat surface for frosting.
Cut the unsalted butter into tablespoon pieces and whip with the paddle attachment until the butter is paler and airy. Alternate adding powdered sugar with the vanilla, heavy cream, and 1–2 tablespoons of sparkling rosé, mixing low to combine and then beating high until the buttercream is light, silky, and pipeable. Fit a large piping bag with a 1M tip, pipe tall swirls of white buttercream onto each filled cupcake, and finish with a glossy strawberry slice and a small green leaf on top for contrast.
