Ingredients:

  • 1 standard box Yellow or Lemon Cake Mix (approx. 15.25 oz / 432g)
  • 1/2 cup (1 stick / 113g) Unsalted Butter, cold and cubed
  • 1 can (14 oz / 396g) Sweetened Condensed Milk
  • 1 tablespoon Fresh Lemon Zest
  • 1/4 cup Fresh Lemon Juice
  • Powdered Sugar, for dusting (optional)

Instructions:

  1. Preheat oven to 350°F (175°C). Line an 8x8 inch baking pan with parchment paper, leaving an overhang to act as a sling, and lightly grease the paper.
  2. In a large bowl, combine the entire box of cake mix and the cubed cold butter.
  3. Use your fingers or a pastry blender to cut the butter into the dry mix until the mixture resembles coarse, damp sand with some pea-sized clumps remaining. This mixture forms both the base and the topping.
  4. Press about two-thirds (2/3) of the crumb mixture firmly and evenly into the bottom of the prepared pan to form the crust. Reserve the remaining one-third (1/3) for the topping.
  5. In a separate small bowl, whisk together the entire can of sweetened condensed milk, the fresh lemon zest, and the fresh lemon juice until just combined and slightly thickened.
  6. Carefully pour the lemon filling mixture evenly over the pressed crust in the pan.
  7. Sprinkle the reserved one-third of the crumb mixture evenly over the top of the filling.
  8. Bake for 30–35 minutes, or until the topping is golden brown and the filling is set (it should not wobble excessively when gently shaken).
  9. Allow the bars to cool completely in the pan on a wire rack (at least 2 hours, or chill for 1 hour) to allow the filling to firm up properly.
  10. Use the parchment sling to lift the slab out of the pan, then slice into 12 squares. Dust with powdered sugar just before serving, if desired.