Preheat oven to 375 F. Use a nonstick spray in a 9 x 13 inch baking dish.
In a large bowl, combine sliced strawberries, sugar, and cornstarch.
Stir well and let sit for 10–15 minutes so the strawberries release their juices and create a thick syrup with the cornstarch.
In a separate bowl, mix cream cheese, sugar, and egg.
Beat until smooth and creamy.
Spread the strawberry mixture evenly on the bottom.
Drop spoonfuls of the cream cheese mixture over the strawberries.
Gently spread cream cheese mixture without mixing with strawberries. I find using the back of a large spoon sprayed with no-stick spray makes this easier.
Sprinkle the dry cake mix evenly over the top. Gently smooth the dry cake layer (do not mix).
Spread butter squares across top of cake mix layer.
Bake at 350°F for 40–45 minutes.The top should be golden brown and the strawberry filling bubbling around the edges.
Notes
Let strawberries sit to release juices before baking - this helps create the syrupy base.If your strawberries are very sweet, you can slightly reduce the sugar.If they are tart, increase sugar slightly for balance.Add an extra ½ tablespoon cornstarch for a thicker filling.Almond extract enhances flavor but should be used lightly.This dessert will be slightly juicier than versions made with canned filling.