Preheat oven to 325 degrees F. In food processor combine nuts and flour Process until nuts are finely ground; set aside. Set aside 2 Tbsp. of the sugar.
Finely shred peel from orange and juice the orange. In a large bowl combine the remaining sugar, 1 tsp of the orange peel, 1/3 cup of the orange juice, the salt, and egg yolks. Beat on high with an electric mixer for 3 to 5 minutes or until very thick and pale.
In another large, clean, dry bowl using clean, dry beaters, beat the egg whites and cream of tartar until soft peaks form when beaters are lifted. Gradually beat in the 2 Tbsp. reserved sugar until the eggs whites are stiff but not dry.
Spoon about a quarter of the egg whites over yolk mixture. Add nut mixture. Fold together with a large rubber spatula. Add the remaining egg whites and fold to combine. Scrape batter into an ungreased 10-inch tube pan with removable bottom; spread evenly in pan. Bake 35 to 40 minutes or until cake is golden brown and springy to the touch and toothpick inserted near center comes out clean. Cool cake upside down in pan by inverting cake pan over a bottle with a long neck.
By the time the cake is cool, most will have pulled away from sides of pan; rap sides of pan sharply on counter to release any portion of cake that is still attached. Run a skewer or long thin spatula around tube to detach; lift to remove cake. Slide a thin spatula around bottom of cake to detach bottom.
Using a sharp serrated knife, cut cake into two layers. Fill layers with Caramel whipped Cream. Serve with Simple Caramel Sauce. Makes 12 servings.
Simple Caramel Sauce
In a small saucepan heat whipping cream and 2 Tbsp. water until steaming hot. Remove from heat; set aside. Place 1/2 cup water in a 2-quart saucepan; pour sugar and salt in a thin stream in center of pan to form a low mound. Don't stir; use your fingers to pat the sugar mound down until it is entirely moistened. Any sugar touching edges of pan should be below the water line. Cover and cook over medium heat without stirring until sugar is dissolved and syrup looks clear. Uncover and continue to cook without stirring until syrup begins to color slightly. Swirl pan gently (rather than stirring ) if syrup is coloring evenly. If syrup gets too dark, it will taste bitter. Use a skewer to drop a bead of syrup on a plate from time to time. When a drop of syrup looks amber (about 13 minutes), remove pan from heat. Holding pan away from you, gradually pour in the hot cream mixture. Stir over low heat to blend the caramel into the cream mixture. Simmer for 1 to 2 minutes. Remove from heat; stir in 1 tsp. pure vanilla extract. Let cool until slightly thickened (220 degrees F-222 degrees F). Serve warm with cake. Store, tightly covered, in the refrigerator up to a week. Makes 12 servings.
Caramel Whipped Cream
Line baking sheet with foil or parchment paper; set aside. Place water in a 2-quart saucepan. Pour sugar in a thin stream in center of pan to form a low mound. Don't stir; use your fingers to pat sugar mound down until it is entirely moistened. Any sugar touching edges of pan should be below the water line. Cover and cook over medium heat for a few minutes without stirring until sugar is dissolved and syrup looks clear.
Uncover and continue to cook without stirring until syrup begins to color slightly. Swirl pan gently (rather than stirring) if syrup is coloring unevenly. Use a skewer to drop a bead of syrup on a plate from time to time. When a drop looks pale amber, add the nuts. Using a silicone spatula gently turn nuts until they are completely coated with syrup. Continue to cook, gently pushing nuts around if syrup is coloring unevenly, until a drop of syrup looks golden amber on the plate (about 30 minutes total). If syrup gets too dark, it will taste bitter. Immediately scrape mixture onto lined baking sheet and spread it out as well as you can. While still warm but cool enough to handle, bread into pieces. Transfer to resealable plastic bag. Keep airtight until needed, so they will not become sticky.
When ready to use, break caramel into smaller pieces; chop medium fine or pulse in food processor. In a large chilled bowl,whipping cream until it holds soft peaks. Fold in chopped caramel. Makes 3 cups.