What You Need:
1 ½ cups whole wheat flour, plus more for dusting
½ tsp. salt
1 stick plus 1 tbsp. cold, unsalted butter, cut into ½ in. cubes
¼ cup cold water
2 tbsp. extra virgin olive oil
4 medium onions (about 1 ½ lbs.), halved and thinly sliced
2 tbsp. coarsely chopped fresh thyme
Fresh ground pepper to taste
3 oz. creamy blue cheese, crumbled (about ¾ cup)
- In a food processor, pulse the flour with the salt. Add the butter and pulse until mixture is pea-sized.
- Sprinkle in cold water and pulse again until the tart dough begins to come together.
- Turn the dough out onto a sheet of plastic wrap and pat into a disk. Wrap the dough and refrigerate until firm, at least one hour.
- Preheat the oven to 400°.
- In a large skillet, heat the oil. Add the onions and cooker medium heat, stirring occasionally until soft, about 25 minutes.
- Reduce the heat to low and continue to cook, stirring occasionally until onions are golden.
- Stir in the thyme and season with salt and pepper. Remove from heat and allow the onions to cool.
- On a lightly-floured work surface, roll out the dough into a 12 in. round. Wrap the dough around the rolling pin and transfer it to a 10 in. fluted tart pan, with removable bottom. Press the dough into the pan and trim off any excess. Use the scraps to patch any cracks. Poke holes in the bottom of the crust with a fork.
- Bake until cruse is lightly browned, about 20 minutes.
- Spread the onions in the tart shell and sprinkle with blue cheese. Bake until the cheese is melted and the onions are warm, about five minutes.
- Cut into wedges and serve.