Before you begin, make sure the butter and cream cheese are at room temperature.
In a stand mixer with a paddle attachment, whip the room temperature butter on medium-high speed for five minutes. You will see a dramatic change-it will go from yellow to bright white and fluffy.
Scrape down the sides of the bowl and add in the cream cheese. Mix for another two minutes to completely combine.
Sift the powdered sugar and add into the mixer in two batches, scraping the sides of the bowl in between. Let the mixer run for about 4 minutes and the frosting will be thick and velvety.
Add the vanilla extract, 1 teaspoon of milk and mix to combine.
Make the Fresh Peach Jam
Dice the peaches into 1/4 inch pieces.
In a heavy bottom pan, combine the peaches, sugar, and lemon juice. Cook over low heat for 30 minutes, stirring occasionally.
Press down on the peaches with the back of a spoon to break up most of the large chunks. Let the jam cool before transferring to a piping bag.
Fill the Macarons
Pair matching macaron shells and pipe the frosting onto the center of one shell. Pipe about 1/4 tsp of peach jam into the center of the frosting and cover with the matching shell.
Let the macarons rest in the refrigerator for 24 hours before enjoying!
Notes
If fresh peaches are not in season, uset your favorite peach jam!