Quick Recipe Version (TL;DR)
Quick Ingredients
- 700 g cooked roast beef, cut into 2 cm chunks
- 2 large yellow onions (about 500 g), thinly sliced
- 2 tbsp (30 g) unsalted butter
- 1 tbsp (15 ml) olive oil
- 3 tbsp (24 g) all-purpose flour
- 600 ml beef stock
- 2 tsp Worcestershire sauce
- 1 tsp Dijon mustard
- 2 tsp fresh thyme leaves (or 1 tsp dried thyme)
- 1 bay leaf
- 2 tbsp prepared horseradish
- 3 tbsp (45 g) crème fraîche or sour cream
- 1 tsp fine salt, plus more to taste
- 1/2 tsp black pepper, plus more to taste
- 1 sheet puff pastry (about 320 g), thawed if frozen
- 1 large egg + 1 tbsp water (egg wash)
Do This
- 1) Heat oven to 200°C (400°F).
- 2) Slowly brown onions in butter + oil until deeply golden, 18–22 minutes.
- 3) Stir in flour for 1 minute; whisk in stock, then add Worcestershire, mustard, thyme, bay; simmer until thick, 8–10 minutes.
- 4) Stir in roast beef; mix horseradish with crème fraîche and add off-heat. Season to taste; cool 10 minutes.
- 5) Spoon filling into a 1.5–2 L pie dish; top with puff pastry, seal edges, cut vents, brush with egg wash.
- 6) Bake at 200°C (400°F) until pastry is crisp and deeply golden, 25–30 minutes.
- 7) Rest 10 minutes before slicing so the gravy stays thick and spoonable.
Why You’ll Love This Recipe
- Big Sunday-dinner flavor, weeknight-friendly: It’s built for using leftover roast beef, but still feels special.
- Thick onion gravy: Rich, glossy, and deeply savory without being fussy.
- Gentle horseradish kick: Creamy heat that lifts the beef instead of overpowering it.
- Crisp pastry lid: Buttery, flaky crunch on top of a cozy, saucy filling.
Grocery List
- Produce: 2 large yellow onions, fresh thyme (optional), parsley or chives for garnish (optional)
- Dairy: Unsalted butter, crème fraîche or sour cream, 1 large egg
- Pantry: Olive oil, all-purpose flour, beef stock, Worcestershire sauce, Dijon mustard, bay leaf, prepared horseradish, salt, black pepper, puff pastry
Full Ingredients
For the Roast Beef Filling
- Cooked roast beef: 700 g, cut into 2 cm chunks (or thick slices cut into bite-size pieces)
- Yellow onions: 2 large (about 500 g), thinly sliced
- Unsalted butter: 2 tbsp (30 g)
- Olive oil: 1 tbsp (15 ml)
- All-purpose flour: 3 tbsp (24 g)
- Beef stock: 600 ml
- Worcestershire sauce: 2 tsp
- Dijon mustard: 1 tsp
- Fresh thyme leaves: 2 tsp (or 1 tsp dried thyme)
- Bay leaf: 1
- Prepared horseradish: 2 tbsp
- Crème fraîche or sour cream: 3 tbsp (45 g)
- Fine salt: 1 tsp, plus more to taste
- Black pepper: 1/2 tsp, plus more to taste
For the Pastry Lid
- Puff pastry: 1 sheet (about 320 g), thawed if frozen
- Egg wash: 1 large egg mixed with 1 tbsp water
Optional Finishes (Recommended)
- Chopped parsley or chives: 1–2 tbsp, for serving
- Extra prepared horseradish: for a small dab on the side
Step-by-Step Instructions
Step 1: Prep your pan and preheat the oven
Heat the oven to 200°C (400°F) with a rack in the middle. Set out a 1.5–2 L oven-safe pie dish (or similar baking dish). If your roast beef is cold from the fridge, cut it into 2 cm chunks now so it warms more evenly in the gravy later.
Step 2: Slowly caramelize the onions for deep flavor
In a large skillet or sauté pan over medium heat, melt 2 tbsp (30 g) butter with 1 tbsp (15 ml) olive oil. Add the sliced onions and 1/2 tsp of the salt. Cook, stirring often, until the onions are very soft and a deep golden brown, 18–22 minutes.
If the onions start catching on the bottom too quickly, reduce the heat slightly. You’re building the base flavor for the gravy here, so it’s worth taking the time.
Step 3: Build a thick onion gravy
Sprinkle 3 tbsp (24 g) flour over the onions and stir constantly for 1 minute to cook out the raw flour taste.
Slowly pour in 600 ml beef stock, whisking or stirring well as you go to keep the gravy smooth. Add 2 tsp Worcestershire sauce, 1 tsp Dijon mustard, 2 tsp fresh thyme (or 1 tsp dried), and 1 bay leaf. Bring to a simmer and cook until thick and glossy, 8–10 minutes, stirring occasionally.
Step 4: Add the beef, then stir in horseradish cream gently
Reduce the heat to low and stir in the roast beef. Warm it through for 2–3 minutes (avoid simmering hard, which can make the beef chewy).
In a small bowl, mix 2 tbsp prepared horseradish with 3 tbsp crème fraîche (or sour cream). Turn off the heat, then stir this mixture into the gravy. This keeps the horseradish flavor clean and gently punchy rather than harsh.
Remove and discard the bay leaf. Taste and season with the remaining 1/2 tsp salt and 1/2 tsp black pepper, plus more to your liking.
Step 5: Cool the filling slightly (for a crisp pastry lid)
Spoon the filling into your pie dish and let it cool for 10 minutes. This small pause helps prevent steam from softening the pastry from underneath, which is the key to a truly crisp lid.
Step 6: Top with puff pastry and seal well
Lay the puff pastry over the dish. Trim any excess so you have about a 2 cm overhang. Tuck the pastry edge slightly inside the rim or crimp it around the rim to seal.
Cut 2–3 small vents in the top so steam can escape. If you like, lightly score the pastry with a knife (don’t cut all the way through) for a classic look.
Brush the top evenly with the egg wash (egg plus water) for a glossy, deeply golden finish.
Step 7: Bake until crisp, then rest before slicing
Bake at 200°C (400°F) until the pastry is puffed and deep golden brown, 25–30 minutes. If your oven runs hot and the top browns too quickly, loosely cover with foil for the last 8–10 minutes.
Let the pie rest for 10 minutes before serving. This helps the gravy settle into a thick, spoonable texture that won’t run all over the plate.
Pro Tips
- Cool the filling before topping: Even 10 minutes makes a noticeable difference for crisp pastry.
- Keep the horseradish gentle: Stir it in off heat so it stays aromatic and rounded, not bitter.
- Don’t overcook leftover roast beef: Warm it through in the gravy instead of boiling it.
- Thicker gravy equals cleaner slices: Simmer until it coats the back of a spoon and leaves a clear trail when you drag a finger through it.
- Better browning: Egg wash to the edges, plus a couple of steam vents, gives you the most even puff and color.
Variations
- Mushroom and beef version: Add 250 g sliced mushrooms after the onions soften; cook until their moisture evaporates (about 8 minutes) before adding flour.
- Extra creamy horseradish gravy: Increase crème fraîche to 5 tbsp (75 g) for a softer, richer heat.
- Cheddar-crusted lid: Sprinkle 40 g finely grated sharp cheddar over the egg-washed pastry in the last 8 minutes of baking.
Storage & Make-Ahead
Refrigerate: Cool completely, cover, and refrigerate for up to 3 days. Reheat portions in a 180°C (350°F) oven for 15–20 minutes (the oven keeps the pastry crisper than the microwave).
Make-ahead filling: The filling can be made up to 2 days ahead. Cool, cover, and refrigerate. Rewarm on the stove until just hot, cool for 10 minutes, then top with pastry and bake as directed.
Freeze: Freeze baked, cooled pie (well wrapped) for up to 2 months. Thaw overnight in the fridge, then reheat at 180°C (350°F) for 25–35 minutes until hot in the center.
Nutrition (per serving)
Approximate, based on 6 servings: 560 calories; 32 g protein; 35 g carbohydrates; 34 g fat; 3 g fiber; 820 mg sodium.
