Sugar-Free Lemon Bars with Almond Flour

Sugar-Free Lemon Bars

These oven-baked lemon bars have a tender almond-flour crust beneath a thick, tart filling made with fresh lemon juice and zest. Powdered sugar-free sweetener helps keep the filling smooth. The crust is baked first and cooled before the lemon layer goes on, so the two layers stay distinct.

The filling should still jiggle slightly when it leaves the oven. Let the bars cool completely, then chill them before cutting into 9 rectangular portions.

Ingredients for Sugar-Free Lemon Bars

• 2 cups almond flour (190g)
• 3 tablespoons powdered monk-fruit/erythritol baking sweetener, for the crust
• 5 tablespoons unsalted butter, melted (70g)
• 1/4 teaspoon fine salt
• 3 large eggs
• 2/3 cup powdered monk-fruit/erythritol baking sweetener, for the filling
• 1/2 cup freshly squeezed lemon juice
• 1 tablespoon finely grated lemon zest
• 2 tablespoons cornstarch (15g)
• 1–2 teaspoons powdered monk-fruit/erythritol baking sweetener, for dusting
• 2–4 thin fresh lemon slices, for serving (optional)

How to Make Sugar-Free Lemon Bars

1. Prepare the pan: Heat the oven to 350°F (175°C) with a rack in the center. Line an 8-inch square metal baking pan with parchment, leaving overhang on two sides so you can lift out the chilled bars. Lightly grease beneath the parchment if needed.
2. Bake the crust: Stir together the almond flour, 3 tablespoons sweetener, and salt. Mix in the melted butter until evenly moistened. Press firmly into an even layer in the pan. Bake for 14–17 minutes, starting to check at 12 minutes. The crust should look set with lightly golden edges, not deeply browned.
3. Cool the crust and mix the filling: Let the crust cool in the pan until it is no longer hot, about 15–20 minutes. Gently whisk the eggs, 2/3 cup sweetener, lemon juice, zest, and cornstarch until smooth, with no visible dry cornstarch. Avoid vigorous whisking, which adds excess air.
4. Bake the filling: Pour the filling evenly over the intact, cooled crust. Bake uncovered for about 20–25 minutes, starting to check at 18 minutes. The edges should be set, and the center should move slightly as one soft layer rather than ripple like liquid. The top should remain pale yellow.
5. Cool and cut: Cool completely in the pan, then refrigerate for at least 2 hours, until firm. Lift out the slab using the parchment overhang. Cut into 9 rectangular bars with a sharp knife, wiping the blade between cuts.
6. Finish: Lightly dust the bars with the remaining powdered sweetener just before serving. If using lemon slices, arrange them beside the bars rather than on top of the filling.

How to Tell When the Filling Is Set

Gently move the pan when you begin checking at 18 minutes. The edges should look firm, while the center should have a slight, unified jiggle. If it sloshes or ripples, it needs more time. Don’t wait for the hot center to become rigid or the top to brown: the filling firms as it cools, and overbaking can leave it dry or cracked.

Sweetener and Flour Notes

Use a powdered sweetener formulated for baking; some granulated sugar-free sweeteners can leave the filling grainy. Sweetness and bulk vary by brand, so check the product’s conversion guidance. Coconut flour and all-purpose flour are not direct one-for-one substitutes for almond flour in this crust.

Storage and Freezing

Cover and refrigerate leftover bars, and plan to use them within 3–4 days. Keep them chilled until serving, especially in a warm room. Dust just before serving for a cleaner finish; reheating is not needed.

To freeze, place cut bars in a single layer until firm, then wrap and store airtight. Thaw in the refrigerator. The texture may change depending on the sweetener and crust.

Nutrition

Approximate nutrition per bar, based on 9 bars: 210 calories, 7g protein, 19g fat, and 19g carbohydrates. Approximate nutrition per 100g: 285 calories, 9g protein, 25g fat, and 25g carbohydrates. Estimates include the sweetener’s labeled carbohydrates; values vary by brand and by how sugar alcohols are counted on the label.