Prep the Base: Preheat your oven to 350°F (175°C). Grease your 9x13-inch baking dish. Spread the lemon pie filling evenly across the bottom.
Cream Cheese Layer: In a small bowl, whip the softened cream cheese with the sugar and vanilla extract until smooth. Dollop this mixture over the lemon filling and smooth it out gently with your spatula.
Add Cake Mix: Sprinkle the dry yellow cake mix evenly over the entire surface, covering both the lemon and cream cheese layers.
Butter: Place the thin pats of butter all over the top of the cake mix, covering as much surface area as possible.
Bake: Pop it in the oven for 40–50 minutes, or until the top is golden brown and the edges are bubbling with delicious lemon goodness.
Serve: Let it cool for at least 15 minutes before serving to let the layers set. Top with fresh lemon zest if desired and serve warm with a scoop of ice cream.