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Grain-Free, Low Carb Lemon Whoopie Pies

by Kate Itrich-Williams September 17, 2019

Lemon Whoopie Pie

A classic whoopie pie sandwiches fluffy frosting or marshmallow fluff between two pillowy, cake-like cookies. It's a generous, decadent treat, perfect for adapting, KNOW Foods-style. The cookie part is easy — simply unwrap two KNOW Better Cookies of your choice. We're using lemon here, but any flavor will work.

For our filling, we've adapted a Swiss meringue-style buttercream to use KNOW Better Sweetener. Our recipe is a riff on the foolproof buttercream from Stella Parks over at Serious Eats. For best results, use a kitchen scale to measure your ingredients and pay close attention to everything's temperature. It will take some time and attention to pull it off, but once you've made a batch, you'll have frosting for days. (Freeze any extra in an airtight zipper lock bag. Thaw in the fridge then bring to room temperature before re-beating with a mixer and serving.)

Don't want to go through all that trouble? Fill your whoopie pies with a double batch of our KNOW Better Cream Cheese Frosting.

Serves 8, with extra frosting


11 ounces (1 3/4 cups) KNOW Better Sweetener
6 ounces egg whites (from about 6 large eggs)
3/4 teaspoon kosher salt
1/4 teaspoon lemon juice
20 ounces (5 sticks) unsalted butter, at cool room temperature (about 65 degrees)
8 KNOW Better Lemon Cookies


Fill a medium saucepan with about 2 inches of water. Place over medium heat and bring to a gentle simmer.

Meanwhile, in a medium to large heatproof mixing bowl, combine the sweetener, egg whites, salt and lemon juice. Place the bowl in the saucepan, making sure that it does not touch the bottom of the pot. While stirring constantly with a rubber spatula, cook the sweetener mixture until it reaches 170 degrees, 15 to 20 minutes.

Transfer to the bowl of a stand mixer fitted with the whisk attachment.

Turn the mixer to high speed and beat until the mixture is glossy, thick, opaque, and relatively cool (about 90 degrees), about 10 minutes. With the mixer running, add the butter, 1 to 2 tablespoons at a time. The frosting will look runny as you're adding butter, but it should thicken up and turn light at fluffy as the final few pieces of butter are added. Turn the mixer off, scrape down the sides and bottom of the bowl, and then beat on high for another few seconds to incorporate any unmixed sweetener mixture.

Transfer about half of the frosting to a piping back or zipper lock bag. (Reserve the remaining frosting for another use; see note.) If using a zipper lock bag, snip off about 1/4 inch of one corner. Pipe around 1/3 cup frosting onto the flat surface of four of the cookies. Top with the remaining cookies. Serve.


Per Serving (1/2 whoopie pie): 469 calories, 44 grams fat, 6 net carbs, 9 grams protein

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