A crisp butter crust spread thickly with Dijon mustard, covered with sliced tomatoes and herbs, and baked until the tomatoes start to brown. A French home supper for late summer and early autumn, served warm with a green salad.
Of all the savoury tarts, this is the one I make on weeknights, as long as the pastry is made ahead: then it's mustard, tomatoes and under an hour in the oven. It also uses the jar that's always open in a French fridge, strong Dijon mustard, and in mine that's Maille.
Maille isn't overly expensive here, and one 200 mL jar covers about four tarts at 3 tbsp each. When the supermarket brand is what's open instead, it works too. Outside late summer, skip the big pale tomatoes: Romas or the smaller ones sold on the vine have more flavour and less water.
A tart from the French home kitchen
Shortcrust spread with a thick layer of mustard, sometimes a little grated cheese, then sliced tomatoes, herbes de Provence and olive oil. The mustard bakes into a mellow, tangy layer, nowhere near as sharp as it tastes from the jar.
Which Dijon is strong enough?
French supermarket Dijon makes your nose tingle, and that heat is what survives the oven. Buy a jar labelled Dijon, not 'Dijon-style' or honey Dijon:
Maille Dijon Originale is the one I use and the French reference; Voilà by Sobeys lists it in 200 mL and 500 mL jars.
French's Dijon, at Walmart and Sobeys, is made with Canadian mustard seed and white wine.
Taste a little on a spoon first. If it barely tingles, use 4 tbsp instead of 3. More on jars in the French mustard guide.
Keeping the crust crisp under tomatoes
Tomatoes are mostly water, and every bit of it wants to go into the pastry. Salting and draining the slices, blind-baking the crust and spreading the mustard on the hot base all keep the juice where it belongs.
Making it in Canada
The 2 French ingredients, and what to buy for them in Canada.
A French pâte brisée is all butter and unsweetened, which is what you want under mustard. Tenderflake shells are lard or shortening and deep, so the tomatoes sit in a puddle. The pastry below takes 10 minutes plus 30 minutes in the fridge.
🛒 For something ready-made with butter, use puff instead (see the Notes): PC Butter Puff Pastry (450 g) at Maxi in Quebec and Loblaws elsewhere, or Première Moisson pur beurre (400 g) at Metro. Tenderflake Puff Pastry is margarine, with no butter.
Emmental ou comté râpé→Oka, grated cold, or leave it out
The cheese is optional. Oka melts as smoothly as Emmental but tastes earthier, which stands up to the mustard; use 50 g.
🛒 Oka Original (190 g) at Walmart and Sobeys. For the nutty taste of the French version, Swiss Gruyère if you see it: Emmi (150 g) at Walmart, Le Superbe Le Gruyère (195 g) at Metro.
Good to know: Make it while Canadian field tomatoes are still around in early fall; in winter, use Romas or tomatoes on the vine and salt them the full 15 minutes.
Ready to cook?
Tomato Mustard Tart
Tarte à la tomate et à la moutarde
A crisp butter crust spread thickly with Dijon mustard, covered with sliced tomatoes and herbs, and baked until the tomatoes start to brown. A French home supper for late summer and early autumn, served warm with a green salad.
Prep time
30 min
Cook time
50 min
Resting time
50 min
Total time
2 hr 10 min
Servings
6
Chill the pastry 30 minutes and the lined pan 10, then cool the baked tart 10 minutes before slicing.
Ingredients
Original recipe: 6 servings.
Instructions
Make the pastry. Mix the flour and salt. Rub in the butter with your fingertips until it looks like coarse crumbs with a few pea-sized bits left. Add the yolk and 3 tbsp ice water and press together with a fork, adding the last spoon only if it's too dry to hold. Flatten into a disc, wrap and chill 30 minutes.
Drain the tomatoes. Lay the tomato slices on a double layer of paper towel, sprinkle lightly with salt and leave 15 minutes. Pat the tops dry.
Line the pan. Heat the oven to 200°C (400°F). Roll the pastry 3 mm thick and line a 24 cm (9½ in) tart pan with a removable bottom. Prick the base and chill 10 minutes.
Blind-bake. Line the pastry with parchment, fill with dried beans or pie weights and bake 15 minutes. Remove the paper and weights and bake 5 minutes more, until the base looks dry.
Fill. Spread the mustard over the hot base and scatter over the cheese, if using. Arrange the tomato slices on top, overlapping slightly, then sprinkle with the herbs and some pepper and drizzle with the olive oil.
Bake. Bake on the lowest rack 25–30 minutes, until the tomatoes are soft and browned at the edges and the crust is golden. Cool 10 minutes before slicing.
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Notes
Make ahead: the pastry keeps 2 days in the fridge, or freeze the lined pan for up to a month and blind-bake it from frozen. That's what makes it a weeknight tart.
Slices thinner than 1 cm dry out; thicker ones leak juice.
With butter puff pastry instead of shortcrust, skip the blind-bake: roll it out, prick it well, fill it and bake on a sheet at 200°C (400°F) for 30–35 minutes.
Best warm, the day it's baked. Keeps 2 days in the fridge; reheat at 180°C (350°F) for 10 minutes.
Course: Mains · Cuisine: French · Adapted for Canadian kitchens
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Most frozen puff pastry in Canada is made with margarine, not butter: fine for cheese straws, flat in a galette des rois. Which blocks contain butter, why pâte brisée is worth making yourself, and quick brisée, sablée and rough puff.
For moutarde de Dijon, buy smooth Dijon, never yellow mustard, and taste it for heat first. For moutarde à l'ancienne, buy whole-grain mustard, often labelled "old style" here. Much French Dijon is made with Canadian seed anyway.
