Rustic Potato and Caramelized Onion Tart

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.