Preheat & Prep: Heat oven to 350°F / 175°C. Line muffin tin with paper liners.
Mix Dry Ingredients: Whisk flour, baking powder, and salt in a bowl. Stir in crushed strawberries if using.
Cream Butter & Sugar: In another bowl, beat butter and sugar 2–3 minutes until light and fluffy.
Add Eggs & Vanilla: Beat in eggs one at a time, then add vanilla. Scrape bowl as needed.
Combine: Alternate adding dry mix and milk, starting and ending with dry. Mix until just combined. Add pink food coloring for desired shade.
Bake: Divide batter evenly among liners (about ⅔ full). Bake 18–21 minutes or until a toothpick comes out clean. Cool in pan 5 minutes, then on rack.
Make Buttercream: Beat butter until smooth. Add powdered sugar gradually. Mix in vanilla, salt, and cream until fluffy. Tint pink and add strawberry jam or powder if desired.
Decorate: Pipe or spread buttercream onto cooled cupcakes. Finish with sprinkles or edible glitter.