Key Lime Pie Is Weight Watchers Classic

Make a Weight Watchers version of Key Lime Pie that is only 4 points per slice! This Key Lime Pie is different from other WW versions, which are usually no-bake Key Lime Pies that use Jello mix or Cool Whip. But I wanted something that was closer to a traditional Key Lime Pie, so I created this recipe!

This is a custardy Key Lime Pie from scratch that you bake in the oven. Instead of condensed milk, I utilized fat-free evaporated milk with zero-calorie sweetener and cornstarch to make it thicker. It has some egg yolks for richness, which is why it has such a velvety texture. This pie is the ultimate harmony of light, creamy, and rich flavors and textures. The lime amount is just right and isn’t too tart. The filling has a nice balance of citrusy and sweet notes. On the surface, it forms a yummy, sugary layer from the sweetener crystalizing while it bakes. What a treat!

I will say that this recipe requires a careful hand. The filling is first cooked on the stovetop, and you need to cook it gently over low heat so the eggs don’t curdle! So you’ll definitely want to save this recipe for a day when you can take your time and really enjoy the process. Once you take a bite into the tasty key lime pie, all the effort will be worth it! It’ll be the best key lime pie recipe you’ve made, and it is far healthier than the average!

Why You Should Try This Recipe

• It’s healthy. This is a low-fat and low-calorie dessert! Per slice, it only has 105 calories and 2.1 grams of fat. So, this is a great, healthy option for when you have a sweet tooth.
• It requires simple ingredients. You don’t need any fancy ingredients to make this recipe! Everything can be picked up at your local grocery store. And if you can’t find key limes, it is okay to use bottled juice with no added sugar.
• Homemade is always better. Making things from scratch is not only good since you know what exactly goes into it, but it also tastes better, and it’s so rewarding to make it yourself!

Recipe Overview

• Serving Size: 1 slice (105g)
• Number of Servings: 8
• Time to Cook: 1 hour
• WW Points Per Recipe: 4 per serving, 34 for the entire recipe. (Click here to view the recipe in the WW app. WW login required)

Ingredients in Key Lime Pie

Key Lime Pie Filling

• ⅔ cup Key Lime juice
• 3 Egg yolks
• 12 fl oz Fat-free evaporated milk
• 1 cup Zero-calorie sweetener (use a cup-for-cup sugar replacement like monk fruit powder)
• ¾ tsp Vanilla extract
• ½ cup Plain, unsweetened Almond milk
• 5 tbsp Cornstarch

Graham Cracker Crust

• 4.5 oz Low-fat graham cracker crumbs
• 2 tbsp Zero-calorie sweetener (use a cup-for-cup sugar replacement like monk fruit powder)
• 3-5 tbsp Unsweetened applesauce

How to Make Key Lime Pie (Step by Step)

1. Preheat the oven to 325°F. Make the crust. In a large bowl, combine the graham cracker crumbs, low-calorie sweetener, and applesauce. Start with three tablespoons of applesauce and add one to two more tablespoons if needed. The mixture should bind together without being dry.

2. Press the Graham cracker crust into a greased 8-inch or 9-inch pie dish. Bake the crust for 10 to 15 minutes or until it feels firm and set.

3. While the crust par-bakes, start making the filling on the stovetop. In a pot, add the vanilla extract, almond milk, and evaporated milk. Heat on low until it is warm, but don’t let it boil.

4. In a bowl, combine the lime zest and sweetener, massaging the zest with the sweetener granules to extract the oils. Add the cornstarch and whisk to remove any lumps. Make a paste by mixing the sweetener mixture with the yolks and lime juice.

5. Once the milk mixture is hot, slowly add and whisk in the slurry. Keep the temperature at med-low heat and constantly stir the mixture. I like to use a rubber spatula while stirring, so it picks up any gelled parts on the bottom of the pan and prevents it from curdling. (tip: it should never bubble! Overheating will destroy it.) Cook for about 15-20 minutes or until it begins to thicken. It should be thick enough to coat the back of a spoon.

6. Let sit for 5 minutes after removing from heat. Pour the filling into the prepared graham crust. Use a toothpick to pop any bubbles on the surface, or gently tap the pan on the table to pop them.

7. Bake the pie for 25-30 minutes and check on it. It should be set on the edges. If the center is still wet, reduce the oven temperature to 250°F and bake for another 5-10 minutes or so until the center still slightly jiggles but isn’t sloshy. It should have an internal temperature of 145ºF read with a kitchen thermometer when it is done, and shouldn’t have browning. Be careful not to overbake because it will turn grainy. 

8. Allow the pie to cool to room temperature before transferring it to the refrigerator and allowing it to firm up. This pie has the best texture when you serve it the same day you make it!

Variations and Substitutions

• Regular Limes: If key limes aren’t accessible to you, you can make this key lime pie with regular limes, like Persian limes, but it will taste slightly different.
• Key lime Pie Bars: Turn this recipe into dessert bars that you can slice into squares! I haven’t tried it, but the crust should fit into a 9 x 13 pan. The batter will spread out and be thinner, so they won’t need to bake as long. Keep an eye on them!
• Key Lime Pie with Meringue: If you want a fancy topping to make your pie stand out, make homemade meringue to decorate the top. This will surely give the pie a stunning look! For the meringue, you can either brown it with a kitchen torch or put it in a 450F oven for a few minutes.
• Sweetener vs Sugar: This recipe works best with sweetener because of the amount needed. Typical recipes have sweetened condensed milk, but since this recipe uses evaporated milk, we need a lot of zero-calorie sweetener to ensure that the pie doesn’t come out much too sour from the lime juice. Therefore, if you swap sweetener with granulated sugar, it will increase the Weight Watchers points to 12 points per serving.
• Milk Type: You can also use skim milk instead of plain unsweetened almond milk and it will turn out great!
• Topping Ideas: You can make this key lime pie with Cool Whip topping for a pretty presentation. Use fat-free Cool Whip to keep the points low! Depending on how many points you have, you can also decorate it with classic whipped cream or simply garnish it with extra lime slices and zest.

Tips and Tricks for Making the Best Key Lime Pie

• Using med-low heat on the stovetop is crucial. Since this is a custard recipe with eggs, you might accidentally scramble the eggs or curdle the mixture if the heat is too high. This is a recipe that you must cook low and slow!
• If the graham cracker crust is too sticky to spread out in the pan, you can place it in the freezer for a few minutes. It will make it easier for you to spread and press into the pie tin.
• The key lime filling should be like a thick gravy consistency when you remove it from the stove top. It’s very important to make sure it is already somewhat thickened before you begin baking it in the oven, otherwise, it won’t properly set.
• Allow the pie to set before slicing it. It needs resting time in the fridge to become firm enough. This pie is best enjoyed the same day you make it but if you have leftovers, keep it covered in the fridge.

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