1️⃣ Make the Raspberry Swirl

1. In a saucepan, combine raspberries, sugar, and lemon juice over medium heat.
2. Stir occasionally and cook until the raspberries break down (about 5 minutes).
3. Strain the mixture if you prefer a seedless swirl.
4. Let the raspberry puree cool completely before using.

2️⃣ Prepare the Cupcake Batter

1. Preheat oven to 350°F (175°C) and line a muffin tin with cupcake liners.
2. In a bowl, whisk together flour, sugar, salt, baking powder, and baking soda.
3. In another bowl, whisk together melted butter, eggs, milk, and vanilla extract.
4. Combine wet and dry ingredients and mix until just combined (do not overmix).

3️⃣ Swirl in the Raspberry Mixture

1. Fill cupcake liners ¾ full with batter.
2. Drop ½ teaspoon of raspberry puree on top of each cupcake.
3. Use a toothpick or skewer to gently swirl the raspberry mixture.

4️⃣ Bake the Cupcakes

1. Bake for 18-22 minutes, or until a toothpick inserted comes out clean.
2. Let cool in the pan for 5 minutes, then transfer to a wire rack.

5️⃣ Make the Frosting (Optional)

1. Beat softened butter until creamy.
2. Add powdered sugar gradually, mixing well.
3. Stir in vanilla extract and heavy cream/milk until smooth.
4. Frost cooled cupcakes and enjoy!