Preheat oven to 350°. Spray the bottom and sides of a 13×9-inch baking dish with baking spray with flour.
For Cake: In the bowl of a stand mixer fitted with the paddle attachment, beat butter and sugar at medium speed until fluffy, 3 to 4 minutes. Add eggs, one at a time, beating well after each addition. Beat in vanilla.
In a medium bowl, whisk together flour, ground pretzels, baking powder, and salt. Gradually add flour mixture to butter mixture alternately with milk, beginning and ending with flour mixture, beating just until combined after each addition. Pour batter into prepared pan, smoothing top.
Bake until a wooden pick inserted in center comes out clean, 15 to 18 minutes. Let cool completely in pan.
For Filling
In the bowl of a stand mixer fitted with the whisk attachment, beat cream cheese on medium-low speed until smooth, about 1 minute. Add sugar, milk, and vanilla, beating until combined. Scrape down sides of bowl. With mixer on medium-low, slowly add one-third of cream, beating until incorporated. Add remaining cream, and beat on medium until thickened. Spread filling over cake, and refrigerate.
For Topping
In a large bowl, stir together 2 cups boiling water and gelatin until completely dissolved, about 2 minutes. Stir in 1½ cups cold water. Refrigerate until thickened, 45 minutes to 1 hour. Stir in strawberries. Pour over filling, making sure sliced strawberries are evenly distributed. Refrigerate until set, about 3 hours, or until ready to serve.
Recipe by Taste of the South at https://tasteofthesouthmagazine.com/strawberry-pretzel-salad-cake/