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 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
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.