Equipment
* optional
Ingredients
Saltine Crust
- 150 g saltine crackers, crushed into fine crumbs
- 115 g unsalted butter, melted
- 1 egg white, lightly beaten
Caramelized Onions
- 4 yellow onions, thinly sliced
- 15 ml olive oil
- 15 g unsalted butter
- 3 g kosher salt
Custard Filling
- 3 large eggs, room temperature
- 120 ml heavy cream
- 150 g gruyère cheese, freshly grated
- 30 g parmesan cheese, freshly grated
- 2 g fresh thyme, minced
- 2 g black pepper, freshly ground
Nutrition (per serving)
Method
Preheat the oven to 175°C/350°F. Using a food processor or a rolling pin, crush the saltine crackers into fine, even crumbs.
In a medium mixing bowl, combine the crushed saltines with the melted butter. Mix thoroughly until the crumbs are evenly coated and the mixture resembles wet sand.
Press the cracker mixture firmly and evenly into the bottom and up the sides of a 9-inch pie dish. Bake for 10 minutes. If using the egg white, brush it over the hot crust immediately after baking to create a seal against the wet filling.
In a large skillet over medium-low heat, heat the olive oil and butter. Add the sliced onions and kosher salt. Cook slowly, stirring occasionally, until the onions are deeply browned, sweet, and reduced to a jammy consistency. Remove from heat and let cool slightly.
In a large mixing bowl, whisk the eggs, heavy cream, grated Gruyere, grated Parmesan, fresh thyme, and black pepper until well combined.
Spread the cooled caramelized onions evenly across the bottom of the baked saltine crust. Carefully pour the egg and cheese custard over the onions.
Bake the assembled pie in the 175°C/350°F oven for 30 to 35 minutes. The pie is done when the edges are puffed and the center reaches an internal temperature of 74°C/165°F.
Remove the tart from the oven and allow it to rest for at least 15 minutes before slicing. This resting period is crucial for the custard to finish setting.
Chef's Notes
- Patience is the most important ingredient for caramelized onions. Do not rush the process by turning up the heat, or they will fry rather than release their natural sugars.
- Grate your own cheese from a block. Pre-shredded cheeses are coated in anti-caking agents like cellulose that prevent smooth melting and can alter the texture of your custard.
- The egg white wash on the hot crust is a classic pastry technique called waterproofing. The residual heat cooks the egg white instantly, forming a barrier against the wet filling.
- Saltine crackers naturally contain quite a bit of salt, which is why no additional salt is added to the crust or the final custard mixture beyond seasoning the onions.
Storage
Refrigerator: 4 days — Store in an airtight container or wrapped tightly.
Freezer: 1 month — Freezing may slightly alter the texture of the saltine crust, making it softer.
Reheating: Reheat slices in a 175°C/350°F oven for 10-15 minutes to help restore crust crispness.
