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Old Fashioned Lemon Squares Recipe
5 from 24 votes

Old Fashioned Lemon Squares Recipe

Old Fashioned Lemon Squares feature a buttery shortbread crust topped with a tart lemon custard, finished optionally with a lemon-zested powdered sugar glaze. They have a firm yet tender base with a bright and tangy filling that cuts through the richness. These bars are a classic dessert for those who enjoy citrus-flavored sweets.

Prep Time
10 mins
Cook Time
40 mins
Additional Time
2 hrs
Total Time
50 mins
Servings: 24 bars (2x2)
Calories: 233 kcal
Course: Dessert, Baked Goods
Cuisine: American

Ingredients

Shortbread Crust
  • 1 cup butter 2 (8 oz) sticks, softened
  • ½ cup cane sugar regular white sugar may be substituted, all natural
  • 2 cups all-purpose flour I used organic, regular flour may be used, unbleached
  • 1 teaspoon vanilla extract
Lemon Filling
  • 4 large egg
  • 1 ½ cups cane sugar regular white sugar may be substituted, all natural
  • ¼ cup all-purpose flour see notes for how to make Gluten Free, unbleached
  • ⅔ cup lemon juice fresh squeezed; about 4 lemons
  • 1-2 tablespoons lemon about 1-2 lemons, adding more for more tart squares, zest
Powdered Sugar Lemon Glaze (optional)
  • 2 cups powdered sugar
  • 1-2 tablespoons lemon zested, plural
  • 3-4 tablespoons lemon more or less depending on consistency, plural

Instructions

Shortbread Crust
    Cup of Yum
  1. Preheat oven to 350° F (175° C) and line a 9x13 inch pan with parchment paper or foil.
  2. Blend together the softened butter, vanilla, sugar and flour in a mixing bowl or stand mixer on low until smooth and combined.
  3. Press the shortbread batter into the bottom of a parchment lined or well sprayed 9x13 inch baking pan Using a sheet of parchment or wax paper, press the batter evenly into the bottom of the pan. Bake at 350°F (175° C) for 15-20 minutes, just until firm and starting to turn golden.
Lemon Filling
  1. While the crust is in the oven; in a large mixing bowl, whisk together the sugar and flour and lemon zest until it resembles wet sand.
  2. Whisk in eggs into mixture, whisking well until frothy and sugar has dissolved, (cane sugar will take a little longer) then slowly whisk in lemon juice and vanilla. (more is better in my opinion, but I like it tart!)
  3. Pour lemon filling over the hot, baked shortbread crust (or almond flour shortbread crust), returning to the oven for an additional 15-20 minutes. Give the filling a final whisk just before you pour it over the hot crust.
  4. Bake until the filling feels firm when lightly touched give it a jiggle, the center should barely wiggle when it's done. Lemon squares will firm up and set as they cool. Remove from oven and cool on a wire rack.
Lemon Glaze (Optional)
  1. Mix powdered sugar, lemon zest into medium mixing bowl, whisk to combine, slowly add lemon juice, whisking until glaze is desired consistency.
  2. Once the lemon squares have cooled on a wire rack for about 20-40 minutes, then pour and smooth over warm (not hot) lemon shortbread cookie bars.
  3. Cool completely, then cover and refrigerate. *If desired, omit the lemon glaze and dust generously with powdered sugar instead. Be sure to wait until lemon bars are completely cooled.

Notes

  • For gluten free lemon squares, use a high quality gluten free all-purpose flour for both crust and filling; almond flour works well for crust substitution.
  • Cool the lemon squares completely, ideally refrigerate overnight, before slicing to ensure clean cuts.
  • Use a long, sharp knife dipped in warm water and dried between slices to make smooth cutting easier.
  • Serve lemon squares at room temperature or chilled; placing in cupcake wrappers aids in individual servings.
  • Fresh lemons provide the best juice and zest for bright flavor in these bars.

Nutrition Information

Serving 1bar Calories 233kcal (12%) Carbohydrates 38g (13%) Protein 3g (6%) Fat 9g (14%) Saturated Fat 5g (25%) Polyunsaturated Fat 1g (6%) Monounsaturated Fat 2g (10%) Trans Fat 0.3g (15%) Cholesterol 51mg (17%) Sodium 74mg (3%) Potassium 59mg (1%) Fiber 1g (4%) Sugar 27g (54%) Vitamin A 286IU (6%) Vitamin C 12mg (13%) Calcium 14mg (1%) Iron 1mg (6%)

Nutrition Facts

Serving: 24 bars (2x2)

Amount Per Serving

Calories 233

% Daily Value*

Serving 1bar
Calories 233kcal 12%
Carbohydrates 38g 13%
Protein 3g 6%
Fat 9g 14%
Saturated Fat 5g 25%
Polyunsaturated Fat 1g 6%
Monounsaturated Fat 2g 10%
Trans Fat 0.3g 15%
Cholesterol 51mg 17%
Sodium 74mg 3%
Potassium 59mg 1%
Fiber 1g 4%
Sugar 27g 54%
Vitamin A 286IU 6%
Vitamin C 12mg 13%
Calcium 14mg 1%
Iron 1mg 6%

* Percent Daily Values are based on a 2,000 calorie diet.