A question about a recipe: Spring Macaron

I have a question about step 1 on the recipe "Spring Macaron" from StrangeLove. It says:

"Cream butter and cream cheese together. Add milk, vanilla and 2 cups of powdered sugar. Beat to combine. Add 1 more cup of powdered sugar. If it is too thin, add more powdered sugar. I like mine a bit thicker for macarons. Chill for about 2 hours. "

This is probably a silly question but to incorporate the raspberries, shouldn't you cook down the raspberries and strain? Or are they incorporated into the butter and cream cheese mixture?