Preheat the oven to 350°F (175°C) and line a cupcake tin with paper liners.
In a large mixing bowl, whisk together the sifted flour, baking powder, and salt until evenly combined.
In a separate bowl, cream the softened butter and sugar together with an electric mixer or whisk until light and fluffy, about 3-4 minutes, with a pale color and increased volume.
1 1/2 cups all-purpose flour
Add eggs one at a time to the creamed mixture, beating well after each addition, until mixture is smooth and glossy.
1 1/2 cups all-purpose flour
Mix in the watermelon juice, watermelon extract, and vanilla extract until fully incorporated, resulting in a slightly pinkish, fragrant liquid.
1 1/2 cups all-purpose flour
Gradually add the dry ingredients to the wet mixture, folding gently with a spatula or mixing on low speed until just combined and smooth.
1 1/2 cups all-purpose flour
Spoon the batter evenly into the cupcake liners, filling each about two-thirds full.
Bake in the preheated oven for 18-20 minutes, or until a toothpick inserted into the center comes out clean and the tops are lightly golden.
Remove the cupcakes from the oven and transfer them to a cooling rack. Let them cool completely before frosting or serving.
