We love winter squash. A pre-cut package of butternut squash cubes makes a quick steamed side at dinner (and the leftovers go into tomorrow’s green salad).
But for Sunday night dinner, we have the time to do something more creative, like this beautiful tart from California Olive Ranch (photo #1), made with whole wheat flour and two different types of squash.
You can serve it as a first course, or in a smaller slice with the salad course.
For lunch, serve a larger slice with a green salad on the side.
Ingredients For The Crust
1. PLACE a rack in the lower third of the oven; preheat to 350°.
2. WHISK the whole wheat flour, salt, and 1 cup all-purpose flour in a large bowl to combine. Add the butter and work into the dry ingredients with your fingers, smashing between your palms to flatten, until largest pieces are the size of a nickel.
3. DRIZZLE in 6 tablespoons of ice water and rake it in with your fingers. Gently squeeze handfuls of the mixture together until a shaggy dough forms. Turn out onto a work surface and knead until only a few dry spots remain.
4. PAT into a disk and wrap in plastic. Chill until very firm, at least 2 hours or up to 3 days.
5. ROLL out the dough on a lightly floured surface to about ⅛” thick. Transfer to a tart pan. Lift up the edges and allow the dough to slump down into pan.
Gently press the dough into the corners of the pan and trim the excess. (If using springform pan, trim the dough to 1½” up the sides of pan). Freeze until firm, 15–20 minutes, or cover and chill up to 12 hours.
6. Swirl 2 tablespoons of olive oil in a large skillet to coat the bottom and add yellow onions; season with kosher salt. Set the skillet over medium heat and cook the onions—stirring occasionally and making sure to scrape bottom of pan—until very soft and deep golden brown, 15–20 minutes.
Add the garlic and cook, stirring occasionally, until onions are caramelized and deeply browned, 25–30 minutes (if any pieces get super dark and stick to the pan, a few drops of water should dislodge them). Let cool.
7. BRUSH the mustard over the chilled dough, then sprinkle with cayenne. Stir the cheese into the caramelized onion mixture and spread across the crust in an even layer.
8. THINLY SLICE both squashes crosswise, using a mandoline or a very sharp knife. Cut the sweet potato and red onion in half lengthwise, then thinly slice crosswise with a mandoline.
9. ARRANGE the vegetables in concentric circles, with the rounded edges facing up. Start from the outside edge, leaning the slices against the crust, and work your way inward.
10. DRIZZLE the remaining 2 tablespoons of olive oil over the vegetables and season with kosher salt. Bake the tart until the edges of the vegetables are browned (a few spots may even get deeply browned) and the crust is golden brown, 75–90 minutes.
11. DRIZZLE a robust extra-virgin olive oil over the tart. Sprinkle with sea salt and serve.
*A full-bodied, peppery flavor of a Tuscan-style olive oil makes it ideal for savory dishes where you want a pronounced olive oil flavor.