Preheat your oven to 350°F (175°C). Rookie mistake: skipping this step. Don’t be that person.
Mix the magic. In a medium bowl, whisk together sweetened condensed milk and lemon pudding mix until smooth and fully combined. No lumps, unless you like surprise chewy bits.
Pour over crust. Grab your graham cracker crust and pour the lemony goodness evenly over it. Smooth with a spatula if you’re feeling fancy.
Bake. Pop it in the oven for 15–18 minutes. Watch for the edges to look set but the center still slightly jiggly—it’ll firm up as it cools.
Cool it down. Let it sit at room temp for 20 minutes, then transfer to the fridge for at least 1 hour. Patience, young grasshopper.
Slice and serve. Cut into squares or rectangles, dust with powdered sugar if desired, and admire your sunny creation.