Late summer equals loads of luscious tomatoes at the farmer’s market here in New York City, where you’ll find all sorts of heirloom varieties and the acclaimed full flavored “Jersey” tomato. Both kinds are put to good use in this rustic tomato galette Provençal, inspired by the traditional French tomato and mustard tart from that region. This recipe highlights the sweetness of tomato contrasted by the sharpness of Dijon mustard, with a splattering of nutty Gruyère cheese, scented with fresh lemon thyme, all baked in a buttery crust speckled with cracked pepper. 

The galette makes an impressive starter for a summer's eve supper, a light lunch with salad, or even with eggs for a special breakfast.

Rustic Tomato Galette Provençal
Serves 8  
See "Notes" (at the end)  for variations on this adaptable recipe to play around with.

Ingredients
1 recipe savory cornmeal pâte brisée (recipe below)
Dijon or whole grain mustard (I used Maille Dijon)
6-8 ounces shredded Gruyère cheese
½ -1 pint mixed heirloom cherry tomatoes, each cut into 3 to 4 slices depending on size
2 medium tomatoes sliced, I used “Jersey” tomatoes here
Olive oil for drizzling
Fresh lemon thyme (or any variety of thyme) leaves and sprigs
Sea salt to season
Fresh cracked pepper, to sprinkle on crust
1 egg beaten, to brush the crust

First, make the savory cornmeal pâte brisée, refrigerate at least one hour or more until ready to assemble the galette.

Savory Cornmeal Pâte Brisée
Adapted from Martha Stewart’s Baking Handbook, Clarkson Potter 2005

Ingredients
1 c all-purpose flour
1/4 c cornmeal (I’ve used fine ground cornmeal from Goya )
1/2 t salt
1 stick unsalted butter (8 tablespoons) chilled and cut into small cubes
1/4 c ice water, you may wind up using only half of this amount depending on your flour/crust

Note: In warmer weather place the dry ingredients in a metal bowl in the freezer for a few minutes to chill before starting if using the hand method vs a food processor.

Add the cold butter cubes to the bowl with the dry ingredients and toss with your fingers to coat. Then toss, breaking up by rubbing the butter between thumbs and fingers to create flat bits of butter coated with the flour mixture until you have very coarse crumbs.   Add ice water a little at a time, tossing the mixture with your hands just until the dough comes together and you can shape it into a ball.   Turn the dough out on a lightly floured work surface, flatten into a disc, wrap in plastic and refrigerate for at least 1 hour before using.

Method
Preheat oven to 425° F

On a lightly floured piece of parchment roll out the pâte brisée dough into a rectangle, about 1/4 to 1/8  inch thickness. Don't worry if the edges are uneven and crack, once turned up and baked they will look perfectly "rustic". Transfer parchment and dough to a baking sheet, refrigerate until ready to assemble the galette.

Meanwhile, slice the tomatoes letting any excess juice drain.

Assemble the galette:  
Spread mustard ( the thickness is to your taste,  light to heavy ) over the pastry leaving a 2 inch border around the edges.

Scatter the grated cheese unevenly in clusters over the mustard layer.  Sprinkle some of the fresh herb leaves on top ( save some to scatter just before serving).

Arrange the tomato slices, starting with the larger sized Jersey slices to form a ring around the outer edges of the mustard layer. Fill in the center with sliced cherry tomatoes. Drizzle with olive oil and season lightly with sea salt.

Turn up the edges of the galette over the tomatoes, long sides first. Brush the corners that will turn up and overlap with beaten egg (which acts as a glue), then fold up the short ends. Press coarsely ground cracked pepper around the crust border. Brush the crust with the beaten egg wash.

Bake for about 50 to 60 minutes. After 20 minutes reduce oven temperature to 375°, watching closely that the crust doesn't darken too much or burn. Check often and cover the crust edges with foil if necessary. Bake until tomatoes have begun to brown on their edges and crust is golden.

Remove, let cool on a wire rack. Serve warm or best at room temperature when flavors have melded, scatter more fresh thyme leaves over the galette just before serving.

Recipe Notes:  
As with most traditional specialties there are many variations unique to the particular region and cook, giving room for adaptation to what you have on hand in your kitchen. The freshness, quality and flavor of the tomato are what everything else builds around.

• For a more finished, less rustic presentation, use a round, square or rectangle tart pan with a removable bottom. Transfer the dough to the tart pan, trimming the excess dough from the edges.
• Store bought puff pastry can be used instead making the pastry from scratch.  
• Mustard; a traditional Dijon or whole grain can be used, or mixture of both. A rule of thumb is to make the layer as thick as you would on a sandwich depending on your taste preference.  Or, leave the Dijon out altogether (another regional variation) if you’re not a mustard lover, instead serve on the side as a condiment.
• A variety of cheeses can be used. I’ve used Gruyère scattered in mounds, arranging the tomatoes on top. Alternatively, another variation is to arrange sliced rounds of Chevre on top of the tomatoes, while baking the chevre edges will brown and puff up slightly.
• Herbs can be interchanged, use those that marry well with tomatoes like fresh thyme, chervil, or marjoram.

Enjoy!