In a medium bowl, whisk together the butter and sugar.
1 cup unsalted butter, 2 cups sugar
Add in the eggs, sour cream, milk, vanilla and food coloring. Stir until combined.
2 large eggs, 1/2 cup sour cream, 1 & 1/2 cup whole milk, 1 Tbsp plus 1 tsp vanilla, 1 drop pink gel food colouring
Slowly pour wet mixture into the dry mixture. Carefully mix until smooth, try not to overmix.
Divide batter between the 24 liners. Bake for about 25 minutes or until a toothpick inserted in the center comes out clean. Cool completely before frosting.
To make the buttercream:
Whip butter until pale and fluffy. Add 1/2 cup of the strawberry reduction sauce, mix for 1 minute, then scrape the sides and bottom of bowl, mix again for another minute. The butter and strawberry sauce might not completely mix together, but not to worry, when you add the icing sugar, it will come together.
1 cup unsalted butter
Add the icing sugar 1 cup at a time and mix well in between. After the last cup of icing sugar has been incorporated, mix on high for 1 minute or so to make sure the frosting is aerated and smooth.
5 cups icing sugar
Frost as desired. I used a close star tip (Wilton 2D), and starting from the center of the cupcake,
Notes
Cupcakes will stay fresh refrigerated for up to 4 days. Bring to room temperature before serving.