01 -
Heat your oven to 350°F first. Put parchment paper in an 8x8-inch pan, letting it hang over one side.
02 -
Whip the soft butter in your stand mixer for about half a minute until it's light. While the mixer runs, slowly pour in the white sugar. Add the egg and vanilla, mixing until everything blends together nicely.
03 -
Stop the mixer and dump the flour, baking powder, and salt over your butter mixture. Run the mixer on LOW just long enough for everything to form a nice dough.
04 -
Push the dough into your lined pan, spreading it out flat with your fingertips. Cook for 20 minutes until a toothpick stuck in comes out mostly clean. Let it cool all the way down.
05 -
In a fresh bowl, beat the soft butter with cream cheese for a minute until puffy. Stir in vanilla, then slowly add icing sugar while mixing gently. If it's too thick, add a tiny bit of milk.
06 -
After the cookie base cools completely, smooth the cheese topping over the whole thing. Scatter candy hearts or sprinkles on top, then cut into squares and enjoy.