2 large onions, thinly sliced
3 tablespoons olive oil
Crust dough for 1 galette
3 tablespoons Dijon mustard
1 cup Gruyere, white cheddar or kashkaval cheese, shredded
4 large heirloom tomatoes, cut in thick slices
Salt and pepper to taste
1 tablespoon Parmesan cheese
1 egg, beaten
1/4 cup basil, thinly chopped
Sauté onions in olive oil over low flame for 30 minutes until caramelized.
Preheat oven to 400 F.
Roll out dough and place on baking sheet lined with parchment paper.
Spread Dijon mustard evenly on dough, leaving two-inch outer border.
Layer caramelized onions, then add shredded cheese.
Arrange tomato slices to completely cover cheese, then sprinkle with salt, pepper and Parmesan cheese.
Lift edges of dough over tomatoes to create a casing.
Brush dough with beaten egg and bake until crust is golden brown, 30-35 minutes.
Transfer galette to wire rack to cool. Garnish with chopped basil before serving.
Makes 10 servings.