Preheat the oven to 325F then line an 8x8 glass baking pan with parchment paper and set asice.
In a large bowl, whisk the graham cracker crumbs, sugar, salt, and melted butter.
1 & 1/3 cup graham cracker crumbs , 2 tbsp granulated sugar, 1/4 tsp salt, 5 tbsp butter
Press the graham cracker mixture into the prepared baking pan and bake in the preheated oven for 10 minutes.
Once the crust is out of the oven, bring the heat up to 350F and start the filling as the crust cools down.
Make the lemon filling
In another large bowl whisk the sweetened condensed milk, egg yolks, lemon juice, lemon zest, and salt until combined.
2 cans sweetened condensed milk, 4 egg yolks, 2 tbsp lemon zest, 2/3 cup lemon juice, 1/4 tsp salt
Pour the lemon filling on top of the graham cracker crust and bake for 25-30 minutes or until the center is completely set and the internal temperature is 145F.
Let the lemon bars cool down at room temperature until fully cool then transfer to the fridge for 5-7 hours.
Once ready to enjoy, slice and serve. Sprinkle with powdered sugar if desired.