Quick Recipe Version (TL;DR)
Quick Ingredients
- 1 (9-inch) all-butter pie crust (store-bought or homemade), chilled
- 2 1/2 lb (1.13 kg) ripe tomatoes, sliced 1/4-inch thick
- 3 tbsp extra-virgin olive oil, divided
- 2 tbsp unsalted butter
- 2 large yellow onions (about 1 lb / 450 g), thinly sliced
- 1 tsp granulated sugar
- 1 1/2 tsp kosher salt, divided
- 1/2 tsp freshly ground black pepper
- 1 tbsp balsamic vinegar
- 1 tsp fresh thyme leaves (plus more to garnish)
- 1 tbsp Dijon mustard
- 2 tbsp panko breadcrumbs (or fine dry breadcrumbs)
- 8 oz (225 g) sharp cheddar, shredded (about 2 cups)
Do This
- 1. Heat oven to 400°F (205°C). Roast sliced tomatoes with 2 tbsp olive oil, sugar, 1 tsp salt, and pepper for 25 to 30 minutes; cool and blot.
- 2. Caramelize onions in butter + 1 tbsp olive oil with 1/2 tsp salt over medium-low, 35 to 45 minutes; finish with balsamic and thyme.
- 3. Par-bake crust at 400°F (205°C): 15 minutes with weights, then 5 minutes without; cool 5 minutes.
- 4. Brush crust with Dijon; sprinkle breadcrumbs; layer 1 cup cheddar, all onions, roasted tomatoes, then remaining cheddar.
- 5. Bake at 375°F (190°C) for 35 to 40 minutes until bubbly and deeply golden at the edges.
- 6. Cool 20 minutes before slicing; garnish with thyme and serve warm.
Why You’ll Love This Recipe
- Roasting the tomatoes concentrates their flavor so the filling turns rich and jammy, not watery.
- Caramelized onions add deep sweetness that makes sharp cheddar taste even bolder.
- A quick par-bake keeps the crust flaky and crisp on the bottom.
- It’s equally at home for a cozy weeknight dinner or a brunch spread.
Grocery List
- Produce: 2 1/2 lb ripe tomatoes, 2 large yellow onions, fresh thyme
- Dairy: unsalted butter, sharp cheddar cheese
- Pantry: all-butter pie crust, extra-virgin olive oil, granulated sugar, kosher salt, black pepper, balsamic vinegar, Dijon mustard, panko breadcrumbs
Full Ingredients
Crust
- 1 (9-inch) all-butter pie crust (store-bought or homemade), chilled
- All-purpose flour, for dusting (if rolling out)
Roasted Tomatoes
- 2 1/2 lb (1.13 kg) ripe tomatoes (Roma, vine-ripened, or a mix), sliced 1/4-inch thick
- 2 tbsp extra-virgin olive oil
- 1 tsp granulated sugar
- 1 tsp kosher salt
- 1/2 tsp freshly ground black pepper
Caramelized Onions
- 2 tbsp unsalted butter
- 1 tbsp extra-virgin olive oil
- 2 large yellow onions (about 1 lb / 450 g), halved and thinly sliced
- 1/2 tsp kosher salt
- 1 tbsp balsamic vinegar
- 1 tsp fresh thyme leaves
Assembly
- 1 tbsp Dijon mustard
- 2 tbsp panko breadcrumbs (or fine dry breadcrumbs)
- 8 oz (225 g) sharp cheddar, shredded (about 2 cups), divided
- Optional garnish: extra fresh thyme leaves
Step-by-Step Instructions
Step 1: Roast the tomatoes to concentrate flavor
Arrange a rack in the middle of the oven and preheat to 400°F (205°C). Line a large rimmed baking sheet with parchment paper.
Lay the tomato slices in a single layer (it’s fine if edges overlap slightly, but avoid piling them). Drizzle with 2 tbsp olive oil, then sprinkle with 1 tsp sugar, 1 tsp kosher salt, and 1/2 tsp black pepper.
Roast for 25 to 30 minutes, until the tomatoes look slightly wrinkled at the edges and noticeably drier, with some darker caramelized spots. Let cool on the pan for 10 minutes, then gently blot the tops with paper towels to remove excess moisture.
Step 2: Caramelize the onions until deep golden
While the tomatoes roast, set a large skillet over medium-low heat. Add 2 tbsp butter and 1 tbsp olive oil. Once melted, add the sliced onions and 1/2 tsp kosher salt.
Cook, stirring every 3 to 5 minutes (more often toward the end), until the onions are very soft and deeply golden-brown, 35 to 45 minutes. If the pan starts to look dry or the onions are sticking, add 1 tbsp water and scrape up the browned bits (those add flavor).
Stir in the 1 tbsp balsamic vinegar and 1 tsp thyme leaves and cook for 1 minute more. Remove from the heat.
Step 3: Par-bake the crust for a crisp bottom
Keep the oven at 400°F (205°C). Fit the chilled pie crust into a 9-inch pie plate, crimping the edges as desired. Chill the lined pie plate in the refrigerator for 10 minutes (this helps prevent shrinkage).
Line the crust with parchment paper and fill with pie weights or dried beans. Bake for 15 minutes. Carefully remove the parchment and weights, then bake for 5 minutes more, just until the bottom looks dry and lightly golden.
Let the crust cool for 5 minutes. Reduce oven temperature to 375°F (190°C).
Step 4: Add a flavor base that also helps prevent sogginess
Brush the bottom of the warm par-baked crust evenly with 1 tbsp Dijon mustard (a thin layer is plenty). Sprinkle 2 tbsp panko breadcrumbs over the mustard to help absorb any tomato juices that release during baking.
Step 5: Layer onions, cheddar, and roasted tomatoes
Sprinkle 1 cup of the shredded cheddar (about half) over the breadcrumbs.
Spread the caramelized onions evenly over the cheese. Layer the roasted tomato slices on top, overlapping them slightly in a neat pattern. Finish by sprinkling the remaining 1 cup cheddar evenly over the tomatoes.
Step 6: Bake until bubbly and the tomatoes look jammy
Bake at 375°F (190°C) for 35 to 40 minutes, until the cheese is fully melted and bubbling and the crust edges are a rich golden brown. If the crust is browning too quickly at the edges, tent just the rim with foil for the final 10 minutes.
Step 7: Cool briefly, then slice cleanly
Let the pie cool for 20 minutes before slicing. This short rest helps the cheese set so the layers hold together. Garnish with a few extra thyme leaves if you like, and serve warm or at room temperature.
Pro Tips
- Choose the right tomatoes: Roma or paste tomatoes are naturally less watery, but mixing in a few vine-ripened slices adds great fresh flavor. Roasting makes either work well.
- Don’t rush the onions: True caramelization takes time. Keep the heat medium-low and be patient for that deep sweetness.
- Blot the tomatoes: After roasting, a quick blot with paper towels makes a noticeable difference in keeping the crust crisp.
- Shred your own cheddar: Pre-shredded cheese often contains anti-caking agents that melt less smoothly. A block of sharp cheddar gives the best bubbling top.
- Let it rest before slicing: Cutting too early can make the layers slide. A 20-minute cool yields cleaner wedges.
Variations
- Herby version: Add 2 tbsp chopped fresh basil or 1 tbsp chopped chives over the onions before adding tomatoes.
- Smoky cheddar swap: Use 4 oz (113 g) smoked cheddar plus 4 oz (113 g) sharp cheddar for a subtle smoky edge.
- Garlic and heat: Stir 2 minced garlic cloves into the onions for the last 2 minutes of cooking, and add 1/4 tsp red pepper flakes for gentle heat.
Storage & Make-Ahead
Refrigerate: Cool completely, then cover and refrigerate for up to 4 days.
Reheat: For the crispiest crust, reheat slices on a baking sheet in a 350°F (175°C) oven for 12 to 15 minutes, or until hot throughout. (Microwaving works in a pinch, but the crust will soften.)
Make-ahead options: Caramelize the onions up to 3 days ahead and refrigerate. Roast the tomatoes up to 1 day ahead and refrigerate (blot again before assembling). Assemble and bake the pie just before serving for best texture.
Nutrition (per serving)
Approximate, based on 8 servings: 390 calories, 24 g fat, 30 g carbs, 3 g fiber, 13 g protein, 620 mg sodium.
