Preparation Blend first 4 ingredients in processor until nuts are finely ground. Using electric mixer, beat butter, 5 tablespoons sugar, and brown sugar in bowl until blended. Beat in eggs, then ground walnut mixture. (Can be made 1 day ahead. Cover and chill.) Roll out each pastry sheet on lightly floured surface to 10-inch square. Using 5-inch-diameter plate as guide, cut out 4 rounds from each square. Using tip of small knife, score 4-inch-diameter circle in center of each 5-inch round (do not cut completely through pastry). Pierce 4-inch centers thoroughly with fork. Place pastry rounds on large baking sheet. Chill until very cold, at least 1 hour and up to 1 day. Preheat oven to 375°F. Spread 2 1/2 tablespoons frangipane over 4-inch center of each pastry round (reserve remaining frangipane for another use). Arrange banana ovals decoratively on frangipane. Sprinkle bananas on each tart with 1 teaspoon sugar. Bake until pastry is deep golden and bananas begin to brown, about 25 minutes. Brush bananas with warm apricot jam. Sift powdered sugar over tartlets. Serve warm or at room temperature.
Preparation Blend first 4 ingredients in processor until nuts are finely ground. Using electric mixer, beat butter, 5 tablespoons sugar, and brown sugar in bowl until blended. Beat in eggs, then ground walnut mixture. (Can be made 1 day ahead. Cover and chill.) Roll out each pastry sheet on lightly floured surface to 10-inch square. Using 5-inch-diameter plate as guide, cut out 4 rounds from each square. Using tip of small knife, score 4-inch-diameter circle in center of each 5-inch round (do not cut completely through pastry). Pierce 4-inch centers thoroughly with fork. Place pastry rounds on large baking sheet. Chill until very cold, at least 1 hour and up to 1 day. Preheat oven to 375°F. Spread 2 1/2 tablespoons frangipane over 4-inch center of each pastry round (reserve remaining frangipane for another use). Arrange banana ovals decoratively on frangipane. Sprinkle bananas on each tart with 1 teaspoon sugar. Bake until pastry is deep golden and bananas begin to brown, about 25 minutes. Brush bananas with warm apricot jam. Sift powdered sugar over tartlets. Serve warm or at room temperature.