Line a 9×13-inch baking dish with foil, leaving an overhang for easy lifting, and lightly spray with cooking oil.

In a medium bowl, stir graham crumbs with melted butter and a pinch of salt until evenly moistened. Use a flat-bottomed measuring cup to press mixture into the pan’s bottom in an even layer.

Pop the pan into the fridge for at least 10 minutes—this firms up the crust so it won’t crumble under the filling.

In a large bowl, whisk room-temp cream cheese until smooth, then gradually add powdered sugar. Scrape down the sides to avoid lumps.

Gently fold whipped topping or whipped cream into the sweetened cream cheese until just combined; don’t overmix or you’ll lose airiness.

Remove the crust from the fridge and evenly spread the cream cheese mixture on top—use an offset spatula for neat edges.

In a separate bowl, whisk sweetened condensed milk with lemon juice and zest until glossy and thick. Taste—if it’s too tart, add a tablespoon more condensed milk.

Carefully spread the lemon-condensed-milk mixture over the cream layer. Cover tightly with plastic wrap and chill for at least 4 hours, or ideally overnight.

Before slicing, top with extra lemon zest or thin lemon wheels. Lift the dessert out using foil overhang and cut into 12–16 squares with a sharp knife dipped in hot water for clean cuts.