Preheat oven to 350°F (175°C) and grease a 9x13-inch baking pan.
In a large bowl, cream together the butter and sugar until light and fluffy.
Add the eggs and vanilla extract, mixing until fully combined.
In a separate bowl, whisk together the flour, baking powder, and salt.
Gradually add the dry ingredients to the wet mixture, mixing until a dough forms.
Press the dough evenly into the prepared baking pan.
Bake for 18-20 minutes, or until the edges are lightly golden.
Allow the cookie base to cool completely before frosting.
For the Frosting:
In a bowl, beat the butter until creamy.
Gradually add powdered sugar, heavy cream, and vanilla extract, beating until smooth.
Add pink food coloring and mix until the color is even.
Spread the frosting over the cooled cookie base.
Decorate with Valentine-themed sprinkles.
Slice into squares or rectangles and serve.