Preheat your oven to 350°F (175°C). Lightly grease your 9×13 inch baking dish with butter or non-stick cooking spray.
Spread the two cans of lemon pie filling evenly across the bottom of the prepared baking dish.
In a mixing bowl, beat the softened cream cheese, granulated sugar, and vanilla extract until the mixture is smooth and free of large lumps.
Drop small spoonfuls of the cream cheese mixture over the lemon pie filling. Use a knife or spatula to gently swirl the cream cheese into the lemon layer, creating ribbons of flavor.
Sprinkle the dry yellow cake mix evenly over the top of the fruit and cream cheese layers. Use a spatula to lightly level the mix, but do not stir it into the bottom layers.
Drizzle the melted butter evenly over the entire surface of the cake mix, ensuring you cover as much dry powder as possible to avoid powdery spots.
If using, sprinkle the sliced almonds over the top.
Bake for 40 to 45 minutes, or until the top is golden brown and the edges are bubbling. The center should be set but still slightly soft.
Allow the cake to cool on a wire rack for at least 20 minutes before serving to ensure the filling stabilizes.