Heat oil in medium saucepan over medium-high heat until hot; add onion and garlic. Cook 2 minutes or until onion is tender. Add tomatoes with juice, tomato paste, salt and red pepper; bring to a boil. Reduce heat to low; simmer, uncovered, 30 minutes or until mixture reduces to 1 1/3 cups. Remove from heat; set aside.
Meanwhile, combine cream, Parmesan and ricotta cheeses and black pepper in medium bowl; beat with electric mixer at medium speed until smooth. Set aside.
Brown sausage in large skillet over medium-high heat until no longer pink, stirring to separate meat. Drain sausage on paper towels; set aside.
Preheat oven to 375 degrees F.
Roll out 1 pastry sheet to 13-inch square on lightly floured surface with lightly floured rolling pin. Press pastry onto bottom and up side of 9-inch springform pan. (Pastry will not completely cover side of pan and will hang over edge in places.) Layer of cooked sausage on bottom of pastry shell. Top with of reserved tomato sauce mixture, spreading evenly. Drop of cream cheese mixture by heaping teaspoonfuls over tomato sauce mixture. Arrange of Gruyere in pastry shell, forming solid layer. Spread pesto evenly over Gruyere. Arrange remaining Gruyere over pesto, forming another solid layer. Drop remaining cream cheese mixture by heaping teaspoonfuls over Gruyere. Top with remaining tomato sauce mixture. Layer with remaining sausage. Trim overhanging pastry to an even height with paring knife. Fold pastry over filling. Roll our remaining pastry sheet to 12-inch square on lightly floured surface; trim to 8-inch circle. Make decorative pastry cut-outs from excess dough, if desired. Beat egg yolk and water in small bowl with fork until blended. Lightly brush beaten egg mixture on pastry around filled torta. Carefully place 8-inch circle of pastry over torta, pressing gently to adhere. Lightly brush top crust with beaten egg mixture and arrange pastry cut-outs on top. Brush cut-outs with beaten egg mixture.
Bake 1 hour or until pastry is golden. Let stand 15 minutes on wire rack. To serve, carefully remove side of pan; let stand 45 minutes before cutting into wedges. Garnish as desired.