Quick Recipe Version (TL;DR)
Quick Ingredients
- All-purpose flour 250 g (2 cups)
- Cold unsalted butter 150 g (10 tbsp), diced
- Fine sea salt 3/4 tsp, divided
- Ice water 60–80 ml (4–5 tbsp)
- Large onion 1 (about 200 g), thinly sliced
- Olive oil 1 tbsp + butter 1 tbsp
- Diced ham 200 g (7 oz)
- Shredded low-moisture mozzarella 200 g (2 cups loosely packed)
- Finely grated reggianito (or Parmesan) 100 g (1 cup)
- Large eggs 3
- Whole milk 180 ml (3/4 cup)
- Heavy cream 120 ml (1/2 cup)
- Black pepper 1/2 tsp, nutmeg pinch, dried oregano 1/4 tsp
- Egg wash: 1 egg beaten with 1 tsp water
- Chopped parsley for garnish (optional)
Do This
- 1. Make dough: rub flour, 1/2 tsp salt, and cold butter to coarse crumbs; add ice water until it clumps. Chill 30 minutes.
- 2. Roll and line a 23 cm tart pan; dock and chill 10 minutes. Heat oven to 200°C/400°F.
- 3. Blind-bake 15 minutes with parchment and weights; remove weights, brush with egg wash, bake 5 minutes more.
- 4. Sauté onion in oil and butter 8–10 minutes until soft; add ham, oregano, pepper, and a pinch of salt; cool slightly.
- 5. Whisk eggs, milk, cream, 1/2 tsp pepper, 1/2 tsp salt, and nutmeg. Combine cheeses.
- 6. Fill crust with onion-ham, then cheeses; pour custard. Bake at 190°C/375°F for 30–35 minutes until puffed and golden. Rest 15 minutes, garnish, slice.
Why You’ll Love This Recipe
- Buttery, flaky shortcrust holds a creamy, custardy filling that slices cleanly.
- Classic Argentine combo: jamón, mozzarella, and reggianito for stretchy-meets-savory cheese pull.
- Balanced flavors from sweet sautéed onion, nutmeg, and a touch of oregano.
- Great warm or at room temp—perfect for brunch, lunchboxes, or picnics.
Grocery List
- Produce: 1 large onion, fresh parsley (optional)
- Dairy: Unsalted butter, low-moisture mozzarella, reggianito (or Parmesan), whole milk, heavy cream, eggs
- Pantry: All-purpose flour, olive oil, fine sea salt, black pepper, nutmeg, dried oregano
Full Ingredients
Buttery Shortcrust
- All-purpose flour: 250 g (2 cups), spooned and leveled
- Cold unsalted butter: 150 g (10 tbsp), cut into 1 cm cubes
- Fine sea salt: 1/2 tsp
- Ice water: 60–80 ml (4–5 tbsp), as needed
Savory Filling
- Olive oil: 1 tbsp
- Unsalted butter: 1 tbsp
- Large onion: 1 (about 200 g), halved and thinly sliced
- Diced ham (jamón cocido): 200 g (7 oz), 1 cm dice
- Dried oregano: 1/4 tsp
- Fine sea salt: 1/4 tsp (adjust to taste)
- Freshly ground black pepper: 1/4 tsp
Cheeses
- Low-moisture mozzarella, coarsely shredded: 200 g (2 cups loosely packed)
- Reggianito (or Parmesan), finely grated: 100 g (about 1 cup)
Simple Custard
- Large eggs: 3
- Whole milk: 180 ml (3/4 cup)
- Heavy cream: 120 ml (1/2 cup)
- Fine sea salt: 1/2 tsp
- Freshly ground black pepper: 1/4 tsp
- Ground nutmeg: pinch
To Finish
- Egg wash: 1 egg beaten with 1 tsp water
- Chopped fresh parsley, for garnish (optional)
Step-by-Step Instructions
Step 1: Make the shortcrust
In a large bowl, mix the flour and 1/2 tsp salt. Add the cold butter cubes and toss to coat. Using fingertips or a pastry cutter, work the butter into the flour until you have pea-sized pieces with some larger flat shards remaining. Sprinkle in 60 ml (4 tbsp) ice water and gently toss until the dough just comes together when pressed. Add up to 20 ml (1–2 tbsp) more water if needed. Form a disk, wrap, and chill for 30 minutes.
Step 2: Roll, line, and chill the shell
On a lightly floured surface, roll the dough into a 30 cm (12-inch) round. Lift into a 23 cm (9-inch) tart pan with removable bottom, easing it into the corners without stretching. Trim excess, then fold a slight lip to reinforce the edge. Dock the base with a fork and chill in the freezer for 10 minutes to firm.
Step 3: Blind-bake and seal the crust
Heat the oven to 200°C/400°F with a rack in the lower third. Line the chilled shell with parchment and fill with baking weights or dry beans. Bake for 15 minutes. Carefully remove the weights and parchment, brush the base and sides with egg wash, and bake 5 minutes more until the surface looks dry and set. Set aside. Reduce oven temperature later to 190°C/375°F before baking the filled tart.
Step 4: Sauté onion and ham
While the crust bakes, warm olive oil and 1 tbsp butter in a skillet over medium heat. Add the sliced onion and a pinch of salt; cook, stirring occasionally, until translucent and lightly golden at the edges, 8–10 minutes. Stir in the diced ham, oregano, and pepper; cook 1–2 minutes to warm through. Remove from heat and let cool 5 minutes.
Step 5: Mix cheeses and whisk the custard
In a bowl, combine the shredded mozzarella with the grated reggianito. In a measuring jug, whisk the eggs, milk, cream, 1/2 tsp salt, 1/4 tsp pepper, and a pinch of nutmeg until smooth but not frothy.
Step 6: Assemble the tart
Spread the onion-ham mixture evenly over the par-baked crust. Scatter the cheese blend on top, reserving a small handful if you like a slightly bronzed top. Slowly pour the custard over, tilting the pan gently so it distributes without overflowing. If reserved, sprinkle the remaining cheese over the surface.
Step 7: Bake until puffed and golden, then rest
Reduce the oven to 190°C/375°F and bake on the lower rack for 30–35 minutes, until the tart is puffed, deeply golden at the edges, and the center has a slight, custardy wobble. If browning too quickly, tent loosely with foil for the last few minutes. Cool on a rack for 15 minutes to set before unmolding. Garnish with chopped parsley, slice into wedges, and serve warm or at room temperature.
Pro Tips
- Keep butter cold and visible in small pieces for a flaky, tender crust.
- Brushing the crust with egg wash after removing weights creates a moisture barrier that prevents sogginess.
- Use low-moisture mozzarella and cool the onion-ham mixture before assembling to avoid a watery filling.
- Bake on the lower rack for a crisp bottom and even browning.
- Let the tart rest 15 minutes; it finishes setting and slices cleanly.
Variations
- Spinach and Leek: Sauté 1 thinly sliced leek and 120 g baby spinach until wilted; drain well and add to the onion mixture.
- Roasted Red Pepper: Fold 1 roasted red pepper (peeled, sliced) into the filling for sweetness and color.
- Cheese Swap: Replace half the mozzarella with provolone or Gouda for a smokier profile.
Storage & Make-Ahead
The dough can be made up to 3 days ahead (refrigerated) or 1 month (frozen). The blind-baked crust keeps crisp for 24 hours, wrapped at room temperature. Baked tart: cool completely, refrigerate airtight for up to 3 days. Reheat slices at 160°C/325°F for 12–15 minutes. To freeze, wrap whole cooled tart or slices tightly; freeze up to 2 months. Reheat from frozen at 160°C/325°F for 25–30 minutes.
Nutrition (per serving)
Approximate: 530 kcal; 36 g fat; 24 g carbohydrates; 19 g protein; 1 g fiber; 780 mg sodium. Values will vary based on specific brands and add-ins.
