Butter bottom and sides of a 10x3 inch springform pan. Dust with flour, shake out excess. Line bottom of pan with double thickness of baking parchment. Heat oven to 200°F Heat 2 cups water to boiling in small saucepan. Add pistachios; boil 20 seconds. Drain immediately; spread in single layer on double thickness of paper toweling. While still warm, peel pistachios by pressing between thumb and index finger; or use a small knife. Spread pistachios on baking sheet and bake until dry, about 20 minutes. Cool thoroughly. Grind very fine in nut grinder or chop very fine with a food processor. Press apricot preserves through medium - fine sieve into small bowl with the back of a wooden spoon. Discard any skins left in sieve; reserve sieved preserves. Place almond paste in a smaller bowl. Beat in half and half, 1 tablespoons at a time, until mixture is light and fluffy and has consistency of mashed potatoes, about 4 minutes; reserve. Beat butter in large mixer bowl until light in color, about 2 minutes. Fold in flour, cornstarch, rum, vanilla, and lemon zest with rubber spatula until completely blended. Gradually fold in almond paste mixture; reserve batter. Place egg yolks in large mixer bowl, and gradually beat in 1/2 cup of the sugar at medium speed until mixture is light in color and forms a slowly dissolving ribbon when beaters are lifted, about 5 minutes. Fold into batter with rubber spatula until completely blended; reserve. Adjust broiler rack to accommodate prepared cake pan; top of pan should be about 1-inch from broiler. Place egg whites and salt in clean large mixer bowl. Beat on low speed unrtil soft peaks form. Gradually beat in remaining 1/2 cup sugar, 2 tablespoons at a time; increase speed to medium and beat until whites are stiff but not dry. Fold whites, one fourth at a time, into reserved batter until completely blended. To make torte, spoon a scant 1/4 of the batter into cake pan; brush or spread to edges of pan with pastry brush or small flexible spatula. Place cake pan under broiler; broil until batter is very lightly browned and resembles a cooked crepe, about 3 minutes, depending in temperature of broiler and position of broiler rack. Brush another scant 1/4 cup batter over broiled layer;broil as above. Brush second layer with a thin film of apricot preserves to within 1/2 -inch of edge; sprinkle with about 1 teaspoons ground pistachios. Repeat the layering and broiling process, coating every other layer with preserves and pistachios, until all the batter has been used. You should have about 30 layers in cake pan. Cool torte on wire rack to room temperature; refrigerate, covered, overnight in springform pan. Reserve the remaining apricot preserves, covered; you should have about 1 cup. Reserve remaining pistachios; you should have about 5 tablespoons Remove sides from springform pan. Center an 8-inch template on top of torte. Holding blade of thin sharp knife downward at a 30 degree angle, slice away the sides of the torte from the template to outer rim of the base. Torte will now have 8-inch top and 10-inch base with slanted sides. Trim sides until smooth. Invert torte; remove springform base, and peel off parchment. Place wire rack over torte and invert again. Heat remaining apricot preserves in small heavy saucepan over medium-low heat until candy thermometer registers about 225 degrees, about 10 minutes. Using flat metal spatula, immediately spread preserves evenly over top and sides of torte. Let stand until preserves are cooled and set, about 30 minutes. Make chocolate glaze. Pour slightly cooled chocolate glaze over top of torte. Using flat metal spatula, quickly spread glaze as evenly as possible over top and side of torte, apricot glaze should be completely covered. Let torte stand until glaze is almost set, about 15 minutes. Decorate torte with remaining ground pistachios, as follows: tear off four 3-inch strips of waxed paper; place them under edges of torte to catch any spillings. Sprinkle a 1/2 inch border of pistachios along top edge of torte. Carefully tilt torte at a slight angle and gently press remaining pistachios over sides of torte with small spatula or your fingers. Re-use any pistachios that have fallen onto the waxed paper. Carefully transfer torte to serving platter with large metal spatula. CHOCOLATE GLAZE: (Makes 1/2 cup) Stir butter, rum, corn syrup and salt in small heavy saucepan over low heat until butter is melted. Increase heat to medium and boil mixture, stirring constantly, about 1 minute. Remove from heat. Stir in chocolate until completely melted. Cool at room temperature until mixture coats a spoon, about 5 minutes. Use at once.