Preheat oven to 350°F. Spread quinoa evenly on a rimmed baking sheet. Bake until golden brown, 12-14 minutes; cool about 10 min. (Leave oven on.)
Meanwhile, make the glaze. In a small saucepan, combine glaze ingredients. Simmer, stirring, over medium-low heat until reduced to about ¼ cup, 3-4 minutes. Glaze will harden as it sits. Warm through over low heat just before drizzling over veggies.
Place half of the cooled quinoa in a food processor; process 2 minutes. Transfer to a large bowl. Add remaining toasted quinoa (reserve pan for roasting veggies), almond flour, cornstarch, salt and pepper to bowl; stir to combine. Add oil and egg; stir until mixture is well combined.
Coat a 9-inch-round removable-bottom tart pan with cooking spray. Press crust mixture into bottom and up sides of prepared pan. Using a fork, prick holes all over the bottom of the crust. Bake at 350°F until deep golden all over, about 25 minutes; cool completely on a wire rack.
Increase oven temperature to 425°F. In a large bowl, gently toss the vegetables with olive oil, salt and pepper. Spread the shallots, fennel and squash into a single layer on the reserved pan. Bake for 12 minutes. Scatter Brussels sprouts onto pan and return to oven until vegetables are tender and golden, 10-12 minutes more. Drizzle warm glaze over vegetables. Return to oven for 2 minutes; toss to coat.
While vegetables bake, combine filling ingredients in the food processor; process until smooth and fluffy, 1-2 minutes. Spread evenly in bottom of cooled crust. Remove tart from pan; arrange glazed vegetables evenly over filling. Garnish with pomegranate arils and lacey fennel frond tops.