Purple Sweet Potato Pie with a mound of an Italian meringue inspired by Esther Williams (anyone younger than me will have to google her). I was gifted a box of super fun produce by my friend Chadwick Boyd and in the selection from Frieda’s were a pair of bright purple sweet potatoes. I knew immediately that they would be pie.
With Thanksgiving just a couple days away, how could my mind go anywhere else with such a fun bounty?! The real surprise came with the topping. Sweet potatoes with marshmallows has been a regular on many Thanksgiving tables, so it seemed natural to pile on meringue and toast it like a marshmallow (a pile of whipped cream would be super tasty too).
What I hadn’t planned on was the color. I had reserved the bright purple cooking water after boiling the potatoes, because it was just too pretty to throw away. I typically use a Swiss meringue on a pie, but the Italian version requires making a syrup of sugar and water, which meant I could use my potato water (BOOM, that’s how I’d tint my meringue purple). I had visions of a lavender colored cloud sitting on top of the pie, but when I added the boiling purple syrup to the spinning egg whites it turned bright, bright, bright blue. I’m not entirely sure why, but some chemical reaction in that bowl changed my vision for this pie. I was faced with a bowl of super soft, BLUE meringue and I went for it. I piled it on and then used a star tip to create the swimming cap of a topping (did you look up Esther Williams yet?)
You can see the potatoes and meringue come together in my instagram video and you can also watch me make it on season 2 episode 7 of Zoë Bakes on Magnolia Network!
Do you have pie questions or need to troubleshoot your recipe? Check out my guide on how to make pie crust.
- One 9-inch deep dish crust RECIPE HERE (see note)
- 24 oz (680g) purple sweet potato puree (see note)
- 1/2 cup sour cream
- 3/4 cup (150g) sugar
- 3 large eggs
- 1 (12 oz) can evaporated milk
- Pinch salt
- 1 tbsp vanilla extract Homemade Vanilla Extract Recipe
- 1/2 tsp cardamom extract
- 1/2 tsp cinnamon extract
- 2 cups (400g) sugar
- 1 tbsp corn syrup
- 3/4 cup purple sweet potato cooking water strained through a fine mesh sieve
- 6 egg whites
- 1/2 tsp cardamom extract
- 1 egg beaten (for brushing crust)
- Heat oven to 325°F.
- To make the filling: In a large bowl, whisk together the sweet potato puree, evaporated milk, sour cream, sugar, salt, extracts and eggs. Pour into the blind baked pie shell and paint the edge of the crust with the egg wash.
- Bake the pie for about 75 minutes (may take longer depending on the temperature of the ingredients when they go in the oven) or until the sides start to puff and the middle is set, but still slightly wobbly. Cool completely, about 3 hours. The pie will be easier to cut once completely cool or refrigerated.
- Prepare this and pile on JUST BEFORE SERVING! In a small sauce pan fitted with a Candy Thermometer, bring the sugar, purple potato water and corn syrup to a boil over medium-high heat. If any of the sugar crystals get onto the side of the pan, be sure to wipe them down with a wet clean pastry brush. The sugar needs to cook until it hits 248° F on the thermometer. This takes several minutes. Once the sugar syrup has reached 235° F, whip the egg whites in your stand mixer until they are medium peaks.
- Once the sugar reaches the final temperature of 248°F, slowly pour it into the bowl of whipped egg whites while the beater is going on slow. Be sure to pour it along the bowl so that the hot syrup doesn’t hit the beater and splatter. Allow the eggs and sugar mixture to beat on medium high speed until the meringue is light, fluffy, glossy and bright blue. Add the extract and whip for another 30 seconds.
- Mound half the meringue onto the chilled pie. Pipe the remaining meringue onto the mound to create a pattern. Toast the meringue with a Blow Torch just before serving.
18 thoughts to “Purple Sweet Potato Pie”
I believe it’s turning blue due to the change in acidity (just like red cabbage juice), if you would change it’s pH again, it would go back purple (nice DIY science experiment, one could use a bit and add Vinegar or add baking soda and note the difference in colour)
When I steam purple cauliflower, if I add baking soda to the water, it turns blue. Egg whites are alkaline, so the sweet potato turns blue. I wonder if adding a little cream of tartar (or lemon juice) to the egg whites would keep it purple.
I don’t know if I’m missing it but at what temperature and for what duration do you blind bake the crust at with pie weights and then without? I’ve searched through your pie recipes and Instagram videos and can’t seem to find a temp.
Hi Sandra, here are Zoë’s instructions (they are in the ingredient list in the blog post, so you may have missed them!)
Blind baking details: After the dough is in the pan and you’ve frozen it for at least 15 minutes, fill with pie weights, bake at 350°F for about 20+ minutes or until it is golden brown on the edge and set (dry looking in the middle).
I’m having a hard time finding cardamom extract. Any ideas for a substitution?
You can find it on Amazon.
What is the amount of corn syrup used? I don’t see a quantity in the recipe although it’s listed in the directions!!!
Thank you for catching that! It’s just 1 tablespoon. I’ve updated the recipe to reflect that!
Will the pie keep for a day or two in the refrigerator without the meringue?
Hi Rachelle, yes! You can bake it, cool it, and refrigerate 1 day ahead. Just be sure to do the meringue right before serving. Enjoy!
I don’t see how much corn syrup to add. Making the recipe today. Thanks!
Hi Opal! Thank you, it accidentally got omitted from the recipe card. It has been updated now!
Purple Sweet Potato Pie…it was the most perfect Thanksgiving dessert!
I wanted to let you know I made your purple sweet potato pie.
Not only does it look wonderful, but it taste delicious, as well. Thank you very much for wonderful recipe
I love watching you on Magnolia Network
Keep up great job!
The recipe for the crust seems to be different. On the show there wasn’t any shortening in the crust from the show. It also had a bit of vodka.
Is there an updated recipe?
Can you use regular sweet potatoes? Cannot locate purple sweet potatoes?
Hi Debbie, you can definitely use regular sweet potatoes. Happy baking!
I thought I’d try making this with Okinawan sweet potatoes. They are drier than the frida ones so I added a bit more liquid. The color was even better than with the fridas, and it tasted good but the texture was too pasty. I think it would need more fat to give it a proper custard texture.