Caramelized Onion and Spinach Quiche

• porções: 8 servings

Ingredientes

1 cup (125 g) all-purpose flour

¼ cup (31 g) whole wheat flour

1 tsp. Diamond Crystal or ½ tsp. Morton kosher salt

1 tsp. herbes de Provence

10 Tbsp. unsalted butter, sliced ½" thick

Rice flour or all-purpose flour (for dusting)

1 large sweet onion (such as Vidalia), thinly sliced

1 Tbsp. extra-virgin olive oil

1 tsp. Diamond Crystal or ½ tsp. Morton kosher salt, plus more

3 large eggs

3 sprigs thyme, leaves finely chopped

½ cup heavy cream

½ cup whole milk

½ tsp. freshly ground pepper

2 oz. Gruyère, finely grated

1 oz. Parmesan, finely grated

2 cups baby spinach

Instruções

Whisk 1 cup (125 g) all-purpose flour, ¼ cup (31 g) whole wheat flour, 1 tsp. Diamond Crystal or ½ tsp. Morton kosher salt, and 1 tsp. herbes de Provence in a medium bowl. Add 10 Tbsp. unsalted butter, sliced ½" thick, and toss to coat. Using your fingers, smash butter into smaller flat pieces (about chickpea-size). Make a well in center; pour in ¼ cup ice water. Toss with your hands to distribute, then knead in bowl a few times to bring dough together (some dry bits may remain).

Turn dough out onto a surface lightly dusted with rice flour, then dust top of dough with flour. Roll out to a ½"-thick rectangle. Fold dough in half, rotate 90°, and fold in half again. Roll out again to a ½"-thick rectangle; repeat folding process, dusting with more flour as needed to prevent sticking. Pat dough into a ½"-thick disk; wrap tightly in plastic. Chill at least 2 hours and, preferably, up to 12 hours.

Let dough sit at room temperature 5 minutes. Unwrap and roll out on a lightly floured surface to a 12" round about ⅛" thick. Brush off excess flour; transfer to a 9"-diameter quiche or pie pan. Lift edges and allow dough to slump down into pan; press firmly into bottom and sides. Trim, leaving about a 1" overhang. Fold overhang onto itself; press firmly to seal. Crimp edges if desired. Chill 15 minutes.

Place a rack in lower third of oven; preheat to 375°. Place crust on a parchment-lined rimmed baking sheet. Crumple 2 sheets of parchment paper; unfold and line crust. Fill with pie weights or dried beans. Bake until edges of crust are golden brown and bottom is opaque (carefully lift parchment to check), 30–35 minutes. Lift out parchment and weights. Reduce oven temperature to 350°. Bake until golden brown all over, 12–18 minutes.

While the crust is baking, mix 1 large sweet onion (such as Vidalia), thinly sliced, 1 Tbsp. extra-virgin olive oil, and a large pinch of kosher salt in a medium skillet. Cover pan and cook onion over medium heat, stirring occasionally, until softened and translucent, 8–10 minutes. Uncover and cook, adding splashes of water (up to ¼ cup) and stirring and scraping bottom of pan often, until deep golden brown, 12–15 minutes.

Whisk 3 large eggs, 3 sprigs thyme, leaves finely chopped, ½ cup heavy cream, ½ cup whole milk, ½ tsp. freshly ground pepper, and 1 tsp. Diamond Crystal or ½ tsp. Morton kosher salt in a medium bowl. Toss together 2 oz. Gruyère, finely grated, and 1 oz. Parmesan, finely grated, in a small bowl. Spread caramelized onion evenly over crust. Sprinkle half of cheese on top. Scatter 2 cups baby spinach, then remaining cheese over. Pour in egg mixture and lightly press spinach down with a spoon to submerge.

Bake quiche until edges of filling are set but center still wobbles slightly when gently shaken, 45–50 minutes. Transfer to a wire rack; let cool 1 hour before slicing. Do Ahead: Quiche can be baked 2 days ahead. Let cool completely; tightly wrap and chill.