Preheat the oven to 350°. Line a rimmed sheet pan with parchment paper. In a standing mixer bowl or with a hand mixer in a medium bowl on medium speed, blend the butter until it is creamy. Separate the egg white from the yolk and add the egg white to the butter. Discard the yolk. Mix until well incorporated.
In a medium bowl, zest ONLY ½ tablespoon of the lemon. Add in the sugar cookie mix and mix to combine. Add the lemon and sugar cookie mix to the butter and egg white mixture. Mix on medium speed for 2 minutes or until a dough forms
Gather the dough into a ball and cover it with plastic wrap. Place the dough in the freezer for 15 minutes until it is firm.
Remove the dough from the freezer. Form 1-inch sized dough balls and place them 2-inches apart on the prepared rimmed sheet pan. Use your thumb to press a well in the center of each ball of dough. Fill each well with ½ teaspoon of strawberry jam.
Bake for 25 minutes or until the edges of the cookies are slightly browned. Transfer the cookies to a wire rack and cool completely.
Serve the cookies on a serving platter. Enjoy!