1 cup (8 ounces / 227 g) unsalted butter, softened
3 1/2 to 4 cups powdered sugar, sifted if lumpy
2 to 3 tablespoons maraschino cherry syrup
1/4 cup maraschino cherries, drained very well, blotted dry, and minced very finely
1 teaspoon pure vanilla extract
1/4 teaspoon pure almond extract
1 to 2 teaspoons fresh lemon juice
Pinch of fine sea salt
1 to 2 tablespoons heavy cream, as needed
In a large bowl, using a stand mixer fitted with the paddle attachment or a hand mixer, beat the softened butter until smooth and fluffy.
Add the powdered sugar gradually, mixing on low speed until incorporated, then beating until smooth after each addition.
Add the maraschino cherry syrup, vanilla extract, almond extract, lemon juice, and salt. Beat until light, creamy, and evenly combined.
If needed, add heavy cream, 1 teaspoon at a time, to loosen the buttercream. If the frosting is too soft, add a little more powdered sugar until it reaches a smooth, spreadable consistency.
Fold in the finely minced maraschino cherries until evenly distributed.