Tarte aux Moutarde French Tomato Mustard Pie Recipe

Name: Tarte aux Moutarde French Tomato Mustard Pie Recipe
Prep time: 20 min
Cook time: 35 min
Total time: 55 min
Yield: 6
Cuisine: French
Ingredients: 1 pre-made pie crust (or homemade); 3 tbsp Dijon mustard; 4 medium tomatoes, sliced; 1 cup shredded Gruyère cheese (or Swiss); 2 tbsp olive oil; 1 tsp dried thyme (or fresh); Salt and pepper to taste

The first time I made Tarte aux Moutarde, I was convinced I’d ruined it. I slathered on way too much mustard, the crust stuck to the pan, and my tomatoes slid right off like they were on a water slide. But when my friend took a bite and said, “This tastes like France,” I knew I had to keep trying. Now, it’s my go-to summer dish—simple, savory, and just a little fancy without being fussy. Plus, it’s forgiving. Even when I mess it up, it’s still delicious.

Recipe Card

Recipe Title	Tarte aux Moutarde French Tomato Mustard Pie Recipe
Servings	6
Prep Time	20 minutes
Cooking Time	35 minutes
Calories	~250 per slice

Ingredients

1 pre-made pie crust (or homemade if you’re ambitious)
3 tbsp Dijon mustard (the real stuff, not yellow mustard!)
4 medium tomatoes, sliced
1 cup shredded Gruyère cheese (or Swiss in a pinch)
2 tbsp olive oil
1 tsp dried thyme (fresh is better, but I’ve used both)
Salt and pepper to taste

That Dijon mustard? Non-negotiable. Once I tried it with regular yellow mustard because I ran out, and it tasted like a sad hot dog. Gruyère is worth the splurge, but Swiss works if you’re broke. And don’t skip salting the tomatoes—I did once, and the pie was weirdly watery. Learned that the hard way.

Directions

Preheat oven to 375°F (190°C).
Roll out the pie crust into a tart pan (or just a pie dish if that’s all you have). Poke holes with a fork so it doesn’t puff up.
Spread the Dijon mustard evenly over the crust—don’t go crazy, or it’ll overpower everything.
Layer the tomato slices in circles, slightly overlapping. Sprinkle with salt and let them sit for 5 minutes to draw out extra moisture.
Drizzle olive oil over the tomatoes, then sprinkle thyme, pepper, and Gruyère on top.
Bake for 30–35 minutes until the crust is golden and the cheese is bubbly.
Let it cool for 10 minutes before slicing (if you can wait).

The first time, I didn’t poke the crust enough, and it ballooned up like a pillow. Had to deflate it with a fork mid-bake—total chaos. And letting it cool? Yeah, I never do, but it really does help the slices hold together. Otherwise, you’re eating tomato soup on a cracker.

This pie is my summer staple because it’s so flexible. I’ve served it warm, cold, for brunch, even as a weird but delicious breakfast. The leftovers? Even better the next day. Just don’t microwave it—the crust turns into rubber.

Next time, I’m adding caramelized onions. A friend swears by it, and I trust her. Also, maybe less cheese? Nah, who am I kidding—more cheese is always the answer.

Nutrition Info (per serving)

Calories	Carbs	Fat	Protein
250	18g	16g	8g

Honestly, it’s not health food, but it’s not terrible either. I’ve used less cheese and more tomatoes to lighten it up, but then it’s just… sad. If you’re gluten-free, a GF crust works fine—just bake it a little longer. And yeah, it’s vegetarian, but my bacon-loving husband insists it’s better with pancetta. He’s not wrong.

Ingredient Swaps

Ingredient	Substitution
Gruyère	Swiss, Emmental, or even sharp cheddar
Dijon mustard	Whole grain mustard (but NOT yellow mustard)
Fresh tomatoes	Roasted cherry tomatoes (game-changer)

Swiss cheese works in a pinch, but Gruyère has that nutty depth. Whole grain mustard adds texture, but yellow mustard? Just don’t. And roasted cherry tomatoes are amazing—sweeter and less watery. I tried canned tomatoes once… let’s never speak of it again.

Tips

Salt the tomatoes and let them sit—it prevents a soggy crust.
Use a tart pan if you have one; a pie dish works but isn’t as pretty.
Don’t skip the thyme. It’s the secret flavor booster.
Let it cool before slicing (unless you’re like me and just dig in with a fork).

I used to skip salting the tomatoes because I was impatient. Big mistake. The pie turned into a swamp. Now I salt them while I prep everything else—multitasking at its finest. And that thyme? Once I forgot it, and the pie tasted flat. Never again.

FAQ

Can I make this ahead? Yes! Prep the crust and mustard layer, then add tomatoes and cheese right before baking. Or bake it fully and reheat at 350°F for 10 minutes.

Why did my crust shrink? Did you let it rest in the fridge before baking? I didn’t once, and it shrank like a wool sweater in hot water. Chill it for 30 minutes next time.

Can I freeze it? Technically, yes, but the texture’s weird after thawing. Better to eat it fresh or within 2 days.

That’s everything I know about Tarte aux Moutarde! Give it a shot, and don’t stress if it’s not perfect—mine still isn’t half the time. But hey, even the messy versions taste pretty darn good.