Lemon Squares

In my previous post I mentioned that we harvested somewhere in the neighborhood of 25 Meyer lemons from our tree a couple of weeks ago. One of my most favorite lemony things is the humble lemon square. It’s full of flavor and easy to make, and perhaps an under-appreciated treat because grocery store bakeries inevitably botch them by using cheap fats (think palm oil) and fake lemon flavoring.

My recipe is based on one from America’s Test Kitchen and works every time. Do not use bottled juice. You’ll need 2/3 of a cup of freshly squeezed lemon juice ( 5 ounces or 160ml) for this recipe. My Meyer lemons are large and juicy. Just one and a half lemons did the job for me. If you’re using smaller lemons you’ll likely need as many as four. I strongly advise you to pour the juice into a measuring cup and be precise about the amount. Not only will the amount effect taste, but it will impact the ability of the lemon filling to set.

Don’t omit the cream of tartar. It helps to lighten the filling and to firm it up so that it sets, avoiding a disaster in which you’re left with a mess that can’t be sliced.

If you’re new to cooking, do watch this video from Jamie Oliver demonstrating how to separate eggs. 

You will need to separate 3 eggs when you make the filling, using the yolks and saving or discarding the whites.

These little guys are deliciously tart and sweet and decadent, bringing out the baker in a lot us who don’t otherwise get excited about turning on the oven.


Preheat the oven to 350℉ (175℃). 

Get an 8-inch square pan (20cm) ready by creating a foil sling: cut 2 pieces of foil and place them perpendicular to each other, with extra foil hanging over the edges of the pan. Push the foil into the corners and up the sides of the pan, smoothing it flush against the pan. You will remove the squares from the pan by gripping the foil and lifting the whole thing out, therefore make sure there is enough overhanging foil for you to grasp. 

Ingredients for the base:

  • 5 ounces (142 grams) all purpose flour.
  • 1¾ ounces (50 grams) granulated sugar.
  • ½ teaspoon salt.
  • 1 stick (4 ounces/ or 113 grams) unsalted butter.
  1. Whisk flour, sugar and salt together in a bowl.
  2. Melt the butter in the microwave.
  3. Add the melted butter to the flour mixture and stir until everything comes together into a ball.
  4. Transfer the ball to the foil-lined pan.
  5. Using your fingers, press the dough into the pan, trying to make it as level as possible and filling the corners.
  6. Bake until the the crust is golden, about 20 minutes.

While the crust bakes make the filling.

No need to wash the bowl. We’ll use it for the filling.

For the filling:

  • 7 ounces (200 grams) granulated sugar.
  • 2 tablespoons all purpose flour.
  • 2 teaspoons of cream of tartar
  • ¼ teaspoon salt.
  • 6 large eggs.
  • 5 ounces (160ml) fresh lemon juice.
  • ½ stick of unsalted butter (2 ounces or 60 grams) cut into 8 pieces.
  1. Whisk flour, sugar, cream of tartar and salt together in the same bowl you used for the crust.
  2. Break whole 3 eggs into a separate bowl. 
  3. Using the remaining 3 eggs, separate the yolks from the whites and add the yolks to the bowl with the whole eggs. (You can make an omelette from the whites.)
  4. Whisk the eggs until the whites and yolks are combined and pour into the the dry ingredients. Mix until evenly distributed. 
  5. Add the lemon juice and stir.
  6. Cook mixture in a saucepan over medium-low heat, stirring constantly until the mixture thickens and reaches 160℉ (71℃). 
  7. Off heat, stir in the butter until it melts into the filling.
  8. Pour filling over hot crust, spreading it evenly.
  9. Bake until the filling is set, about 10 minutes. Gently shake the pan to see if the filling jiggles a bit. If it juggles rather than runs like a liquid, then it’s ready. If not, bake another minute or two.
  10. Let squares cool for about 90 minutes in the pan.
  11. Once cool, lift them out of the pan and transfer to a cutting board. Slice into desired sized squares.
  12. Dust with confectioner’s sugar before serving. (optional).

Leave a Reply