How to Make It
Preheat oven to 350°.
Place pistachios in a food processor; process until almost ground. Weigh or lightly spoon flour into a dry measuring cup; level with a knife. Add flour, powdered sugar, and 1/4 teaspoon salt to processor; pulse to combine. Add butter; drizzle with oil. Pulse until mixture resembles coarse meal. (It will be dry and slightly sandy.) Press mixture into bottom and up sides of a 9-inch removable-bottom tart pan coated with baking spray. Bake at 350° for 25 to 30 minutes or until golden. Cool completely.
Place blueberries in a medium saucepan; mash with a potato masher. Add juice, 1/3 cup sugar, and cornstarch, stirring with a whisk. Bring to a low boil over medium-high heat, stirring frequently. Reduce heat; simmer 1 minute or until thickened, stirring constantly. Place egg yolks in a medium bowl; add 1/2 cup hot juice mixture to yolks, stirring with a whisk. Pour egg mixture into pan; bring to a boil over medium-low heat. Cook 1 minute or until bubbly and thick, stirring constantly. Remove from heat. Strain through a sieve into a bowl; stir in rind. Place bowl in a larger ice-filled bowl for 20 minutes or until cooled, stirring occasionally. Pour mixture into crust. Cover and chill 3 hours or until set.
Place egg whites in a large bowl. Add vanilla, cream of tartar, and 1/8 teaspoon salt; beat with a mixer at high speed until soft peaks form. Combine 3/4 cup sugar and 1/3 cup water in a saucepan; bring to a boil. Cook, without stirring, until a candy thermometer registers 250°. Gradually pour hot sugar syrup in a thin stream over egg whites, beating at medium-low speed, then at high speed until stiff peaks form. Spread meringue over tart. Garnish with pomegranate arils, if desired.