Heat oven to 325°F. Grease 9x5-inch loaf pan with shortening (do not spray with cooking spray); coat with flour. In 1-quart saucepan, heat 1/4 cup of the butter over medium heat 1 to 2 minutes, stirring constantly, until light golden brown (watch carefully because butter can burn easily). Immediately pour browned butter into large bowl. Cool 10 minutes.
Add remaining 1/2 cup butter, the brown sugar and granulated sugar to browned butter. Beat with electric mixer on medium speed about 30 seconds or until well mixed. Add eggs. Beat on high speed 3 to 4 minutes, scraping bowl occasionally, until light and fluffy. Beat in vanilla.
In small bowl, mix flour, baking powder and salt. Beat flour mixture alternately with milk into butter mixture on low speed, beating just until smooth after each addition. Pour into pan.
Bake 1 hour to 1 hour 10 minutes or until toothpick inserted in center comes out clean. Cool in pan on wire rack 10 minutes. Run thin knife around edge of pan to loosen cake; remove cake from pan to wire rack. Cool completely, about 1 hour 30 minutes.
Cut cake into 3 horizontal layers with a long serrated knife. (Cut top layer first, placing hand on top of cake and cutting from short end to short end, then carefully lift off layer; repeat for middle layer.) Place bottom layer on serving plate.
In medium bowl, beat cream cheese and caramel sundae syrup with electric mixer on low speed until well blended. Gradually beat in whipping cream on low speed. Beat on high speed 1 to 2 minutes or until mixture thickens and soft peaks form. Fold in 3/4 cup of the cashews.
Spread one-third of caramel mixture (about 1 cup) over bottom cake piece. Top with middle layer; spread with half of remaining caramel mixture (about 1 cup). Top with remaining layer of cake. Spread top of cake with remaining caramel mixture. Sprinkle remaining 1/4 cup cashews over top of cake. Cover loosely and refrigerate about 1 hour before serving. Store covered in refrigerator.