Preheat your oven to 350°F (175°C) and prepare an 8x8 inch baking dish with cooking spray.
In a medium bowl, combine graham cracker crumbs, melted butter, sugar, and lemon zest. Press into the bottom of the baking dish.
Bake the crust for about 10 minutes until golden and fragrant, then cool to room temperature.
Mix egg yolks and sweetened condensed milk together until smooth, then add lemon juice and zest.
Gently fold in fresh raspberries.
Pour the filling over the crust and spread evenly.
Bake for an additional 15 minutes until filling is set.
Cool to room temperature, then refrigerate for at least an hour before cutting into squares.
Serve chilled.