Preheat the oven to 350℉. Line a square 8x8-inch baking pan with parchment paper, leaving a bit of an overhang. Set aside.
In a medium bowl, combine the strawberry cake mix, Greek yogurt, melted butter, and vanilla extract with a rubber spatula. Mix well so all of the ingredients are incorporated.
1 15.25 ounce box strawberry cake mix, ½ cup plain Greek yogurt, ½ cup butter, melted, 1 teaspoon pure vanilla extract
Using the spatula, transfer the batter to the prepared baking pan and spread it evenly.
Bake in the preheated oven for 20 to 23 minutes or until the edges start to turn golden brown. Remove the pan from the oven and cool on a wire rack for 15 minutes before removing them from the pan.
Grasp the extended parchment paper edges and remove the bars from the pan. Allow to cool completely before adding the glaze.