Rustic Potato and Caramelized Onion Tart

I have a thing for caramelized onions, if you couldn’t tell. Also, I bought my weight in onions with my last Costco trip. Note to self: stop shopping hungry!

This rustic tart is perfect for brunch or a light dinner, served alongside a crisp green salad. You know what I love about the word rustic? It is a completely endearing way to describe “imperfect”. This tart didn’t adopt “rustic” into its name until my lame attempt at rolling out the dough produced something shaped more like Canada than a circle.

To me, rustic things are made with love, from a well-worn recipe, in a warm home, by a person with weathered hands and flour on their cheek.

This recipe for pastry produces pie dough, perfected. The lard and butter in equal proportions creates a flaky, tender cust with rich, buttery flavour. I have honestly never made better. Try it, if not for this tart, for something sticky-sweet and juicy, like apples or blueberries.

Are you somewhere cold and snowy? Here is something to cheer you up: the first whisper of spring.

Rustic Potato and Caramelized Onion Tart

  • 1 recipe pastry dough (see recipe below)
  • 1 egg yolk
  • 1 1/2 lbs yellow onions, thinly sliced
  • 2 tbsp canola oil
  • 2 tbsp butter
  • 1 tsp sugar
  • 1 lb potatoes, thinly sliced
  • 1 egg
  • 1 cup aged cheddar, shredded
  • 1/2 cup sour cream
  • 1 tbsp fresh sage, minced (or 1 tsp dried)
  • 1 tsp salt
  • freshly ground fresh pepper

Pastry Dough

  • 1 1/2 cups all purpose flour
  • 1/4 cup lard, cubed
  • 1/4 cup butter, cubed
  • 1 tsp vinegar
  • 4 tbsp ice water

1. Make pastry: measure flour (by spooning and leveling into dry measuring cups) into large mixing bowl. Using a pastry blender or two knives, cut in butter and lard until mixture resembles coarse crumbs. Sprinkle vinegar over then ice water over flour mixture 1 tablespoon at a time, tossing with fork until it becomes a shaggy mixture that holds when pressed together. Turn out onto a large piece of parchment paper and use the paper to press the mixture into a disk. Tightly wrap parchment around pastry disk and refrigerate 20 minutes (or up to 3 days).

2. Preheat oven to 425 degrees. Position rack in bottom third of oven. Meanwhile, heat oil and butter in a large stockpot over medium-high heat. Add onions and cook, stirring frequently, until rich golden brown (reduce heat if necessary to prevent burning). Stir in sugar. Spread onions over a large plate to cool.

3. In the same pot, add sliced potatoes. Top with enough cold water to cover by 1 inch. Cover and bring to a boil over high heat. Reduce heat and cook 5 minutes. Drain potatoes in a large colander, running cold water over to cool. In a medium sized bowl, whisk together sour cream, egg, cheese, sage, salt and pepper. Stir in cooled onions.

4. Remove pastry from fridge. Between 2 sheets of parchment paper, roll pastry into a large circle, about 1/4 inch thick (don’t worry about perfection, the goal is “rustic”). Transfer pastry and bottom parchment paper to a rimless (or overturned rimmed) baking sheet. Layer potatoes in a circle on top of pastry, allowing a 2-3 inch border uncovered. Pile onion mixture on top of potatoes. Fold pastry edges around filling, pinching to seal. Brush edges with whisked egg yolk. Bake at 425 degrees for 10 minutes, reduce heat to 375 degrees and continue cooking, about 35 minutes. Serve warm.

  • Krafted by Kelly

    This looks delicious! Thanks for sharing. Seems accessible enough for me to attempt tonight for dinner!

    • Anonymous

      Excellent! Let me know how it turns out for you :-)

  • Sara

    This looks SO good! Love the onions and potatoes…so yummy!

  • Missmopo

    Looks awesome! Been planning on rendering my own lard sometime soon… I think I’ll be trying this recipe with it!

    • Anonymous

      Wow, you’re ambitious. I don’t think I’ll be trying that any time soon…

  • Maggie

    Hey! that’s my pastry recipe! No fair! (Actually, it’s the almost same variation of the Tenderflake Perfect Pastry recipe that I decided to try out Butter is better, right? so 1/2 lard (good) & 1/2 butter (great). The only difference is that I substitute plain yoghurt for the vinegar because I struggle with the idea of putting vinegar in a pastry that I also use for sweet baking.)

    I feel validated by seeing that someone else had the same idea. :)

    • Anonymous

      Great minds think alike! There’s only so many ways to make successful pastry. I haven’t seen the Tenderflake recipe, though – this is just my own version of a basic fat-to-flour ratio.

      P.S. you don’t taste the vinegar in the slightest.

  • Melissa@IWasBornToCook

    This looks truly amazing! So glad I found your blog!

    • Anonymous

      Thank you, and I’m glad you found it, too! :-)

  • Sarah

    I definitely just bought my weight in onions at Costco as well! Guess I’ll just “have to” try out your beautiful and delicious sounding recipe!

    • Anonymous

      That’s the only reasonable thing to do! :-)

  • Michelle

    So glad you shared this one. It looks fabulous!

  • Joanna

    Is there something that can be used instead of lard? Where I live, lard isn’t easily available…The tart looks delicious!

    • Anonymous

      Hi Joanna! You can absolutely use butter instead :-)

  • Sarah

    Potatoes and caramelised onions are two of my favourite things! I’m making this as soon as I possibly can.

  • Greg

    I saw that first picture and went ooooooohhhh.)

  • Marisa

    This recipe combines everything I love most: rich delicious caramelized onions (which make everything better), cheese, buttery pastry & cheese. Oh. my. word. This is a simple recipe that looks so impressive. Thanks!

  • Denise

    I just made this today…call me crazy…I was craving a carmelized onions tart in the summer.  Anyway I found your blog and recipe and here I am…one happy reader!  This recipe is so delicious, it really is perfect for an autumn night.  I cannot wait to bring this to Thanksgiving dinner! 

  • Hannah

    Oh my goodness, this looks SO good! I’ve just stumbled across your wonderful blog this evening and already bookmarked so many recipes to make! x

    • Anonymous

      Aww, thanks Hannah! Happy cooking! :-)

  • Kjussaume

    This was delicious…even with a store bought crust. Was looking for something to make for a New Year’s Eve party with ingredients I had on hand. It got rave reviews!

  • ileana


  • E Scarlet

    This looks really good !
    one question .. can I use butter instead of lard ? I don’t eat pork products ^^

    • Anonymous

      Yes, you can!!

  • Lilgrace

    Just made this for dinner tonight. It’s a keeper for sure! It was loved by all. My youngest had no idea she was eating onions which she normally hates! She ate her whole piece. My only issue was that next time I will re-season the potatoes after I rinse them. Oh, and I did use a store bought pie crust which worked perfectly. I don’t do dough! I didn’t prebake it or anything, just brushed it with milk instead of the egg yolk. Thank you so much for sharing this delightful recipe!

  • Beccajpaul

    Can you give me an idea of how many onions it takes to make a pound and a half?

  • Dbakeca Italia

    looks killer

  • Ashleigh

    I know this was posted ages ago but I’m hoping someone can give some advice. Do you think this tart would be okay after reheating in the microwave the next day?

    • foodess

      Ok as lunch leftovers? YES! To serve guests… not so much.