Spiced Pavlova with Pumpkin Mousse

Ingredients:
4 teaspoons cornstarch
1/4 teaspoon fine sea salt
1 teaspoon ground ginger
1/4 teaspoon ground allspice
1/4 teaspoon ground nutmeg
1/8 teaspoon ground cloves
1 tablespoon plus 1 teaspoon ground cinnamon, divided
6 large egg whites, room temperature
1/2 teaspoon cream of tartar
1 cup superfine sugar, divided
2 large egg whites
1/2 cup granulated sugar
3/4 cup pumpkin purée
1/4 teaspoon kosher salt
1/4 teaspoon vanilla extract
1 1/2 cups pomegranate juice
1/4 cup granulated sugar
2 tablespoons fresh lemon juice
1/2 cup whipped cream
1/3 cup toasted pumpkin seeds (pepitas)
1/3 cup pomegranate seeds

Instructions:
Preheat oven to 275°F. Line 2 rimmed baking sheets with parchment paper. Whisk cornstarch and sea salt in a small bowl, breaking up any lumps. Mix ginger, allspice, nutmeg, cloves, and 1 Tbsp. cinnamon in another small bowl.
Using an electric mixer on medium-high speed, beat egg whites and cream of tartar in a large bowl until soft, opaque peaks form, about 3 minutes. You should see tracks from the whisk on the surface of the whites.
Add superfine sugar slowly, 1 Tbsp. at a time, beating to incorporate fully before adding the next, 5–8 minutes total. Continue to beat on medium-high speed until stiff, glossy peaks form, about 1 minute more. Test to see if sugar is fully dissolved by rubbing a small amount between your fingertips. If it feels gritty, keep beating until dissolved.
Sprinkle cornstarch mixture over egg whites and fold in gently with a spatula. Sift spices over mixture with a fine-mesh strainer and fold in gently.
Using a large spoon, divide meringue into 8 even mounds on prepared baking sheets. Using the back of the spoon, make a small well in the center of each meringue. Using fine-mesh strainer, lightly dust with remaining 1 tsp. cinnamon.
Bake 15 minutes, then reduce oven temperature to 250°F. Continue to bake, rotating sheets halfway through, until outsides are dry and a very pale cream color, 50–60 minutes. Turn oven off and leave door slightly ajar (prop open with a kitchen towel or hot pad) with meringues inside, letting them cool completely, at least 2 hours or up to overnight.
Gently whisk egg whites and granulated sugar in a medium bowl set over a saucepan of barely simmering water until hot to the touch or a candy thermometer registers 140°F.
Pour hot egg white mixture into stand mixer bowl and whip with the whisk attachment on medium-high speed until doubled in volume and stiff peaks form, about 5 minutes.
Whisk pumpkin purée, kosher salt, and vanilla in a medium bowl. Whisk one-third of beaten egg whites into pumpkin mixture to lighten. Gently whisk in remaining whites.
Heat pomegranate juice, granulated sugar, and lemon juice in a medium saucepan over medium-high until sugar is dissolved and juice is simmering. Reduce heat to low and simmer until syrupy and liquid is reduced by half, about 25 minutes.
Divide meringues among plates, then top each with a dollop of pumpkin mousse and whipped cream. Top with pomegranate syrup, pumpkin seeds, and pomegranate seeds.
Pumpkin mousse can be made 1 day ahead; cover and chill. Pomegranate syrup can be made 2 weeks ahead; cover and chill.