Preheat the oven to 350°F (175°C). Generously grease and flour a 6-cavity mini bundt pan, making sure to coat all the detailed grooves.
Pour 1/2 cup of the sparkling rosé into a small saucepan. Bring it to a gentle simmer over medium heat, then reduce the heat and cook until the liquid has reduced to about 1/4 cup. Remove from the heat and allow it to cool completely.
In a large mixing bowl, beat the granulated sugar, vegetable oil, melted butter, egg, egg yolk, and vanilla until well combined. Mix in the sour cream until smooth.
In a separate bowl, sift together the flour, baking powder, baking soda, and salt.
Add half of the dry ingredients to the wet mixture and mix gently. Add the cooled reduced rosé, then add the remaining dry ingredients and remaining 1/2 cup of sparkling rosé. Mix just until the batter is combined.
Add a very small amount of pink gel food coloring. Mix gently until the batter reaches a soft pink shade.
Divide the batter evenly among the prepared mini bundt cavities, filling each about two-thirds to three-quarters full.
Bake for 12 to 15 minutes, or until a toothpick inserted into the center comes out clean or with a few moist crumbs.
Let the cakes cool in the pan for about 10 minutes. Carefully loosen the edges with a thin knife, then turn the cakes onto a wire rack and allow them to cool completely.
To make the glaze, melt the butter in a saucepan over medium heat. Stir in the granulated sugar and water. Reduce the heat and simmer for about 5 minutes, stirring occasionally, until the mixture thickens slightly.
Remove the syrup from the heat and carefully stir in the sparkling rosé.
While the glaze is still warm, poke several small holes in the cooled cakes with a toothpick or fork. Spoon the glaze over each cake and allow it to soak into the crumb.
Let the glaze settle before serving. Add a light dusting of powdered sugar, fresh berries, or delicate sprinkles if desired.
