Pulse first 3 ingredients in a food processor until mixture is crumbly. Slowly add ice water through food chute, pulsing until mixture forms a ball. Flatten dough to a 6" disc; wrap in plastic wrap and chill 1 hour.
Process almonds in food processor until finely ground. Combine almonds, 1/2 cup sugar, and 2 tablespoons flour in a small bowl; set aside.
Beat softened butter, eggs, powdered sugar, and 1/4 teaspoon salt at medium speed of an electric mixer until creamy. Combine almond and butter mixtures. Cover and chill 1 hour.
Roll pastry to 1/8" thickness on a floured surface. Fit pastry into a 10" tart pan; place on a baking sheet. Bake at 425° for 12 minutes. Cool. Reduce oven temperature to 400°.
Combine wine, 2 cups water, 1 cup sugar, and vanilla in a large saucepan; bring just to a boil. Add pears and simmer 8 minutes. Remove from heat. Cool pears completely in liquid. Remove pears and pat dry. Reserve 1 cup poaching liquid.
Cut pears in half vertically, remove cores, and cut pears into 1/4" thick lengthwise slices, keeping stem ends intact.
Spread almond mixture into baked tart shell. Arrange sliced pear halves over almond mixture, stem ends toward center. Fan pears slightly. Brush pears with melted butter. Bake at 400° for 30 minutes or until golden.
Combine reserved 1 cup poaching liquid and cornstarch in a small saucepan, stirring until smooth. Cook over medium heat, stirring constantly, until mixture thickens. Boil 1 minute, stirring constantly. Remove from heat. Brush tart with glaze mixture. Remove sides of tart pan before serving.