Preheat the oven to 350 degrees. Prepare a 9x13 inch baking pan by lining with parchment paper. Set aside. In the bowl of a stand mixer, beat together butter and cream cheese until smooth. Add sugar and beat for another minute.
Add egg to butter mixture and beat until fully incorporated, then add scraped vanilla bean seeds and mix until combined. In a medium bowl, whisk together flour, baking powder and baking soda. Slowly add the flour mixture into the butter mixture and beat until just incorporated, forming a soft dough.
Scoop the dough into the lined pan, and spread evenly. {An offset spatula helps with this.} Bake for 25-20 minutes until the top turns a light golden brown and the dough is set in the center. Remove from oven and let cool completely.
Make the buttercream: In the bowl of a stand mixer, beat together butter, powdered sugar and vanilla until smooth. Add half & half and mix until fully incorporated and smooth.
To make hearts: Using a cookie cutter, carefully cut heart shapes from the cookie base. Separate frosting into several different bowls, but don't forget to leave a small amount of plain white frosting for writing.
Place a drop of food coloring into each bowl; mix until desired color is achieved. Scoop each color frosting into a separate zip-top bag and snip a small tip from each. Use each bag to pipe frosting onto each heart, using an offset spatula to spread it evenly. Use remaining white frosting to pipe phrases onto each heart.