1. Preheat oven to 375°. Spread chopped pecans on a sheet pan, and toast at 375° for 5 minutes; set aside to cool. Line 2 greased 9-inch round cake pans with wax paper, and set aside.
2. Lightly spoon flour into a dry measuring cup; level with a knife. Sift together flour and next 4 ingredients. Cream butter and sugar together in a large bowl using an electric mixer on medium speed. Reduce speed to medium-low, and add eggs 1 at a time, blending well after each addition. Add milk and half of flour mixture; blend well. Add remaining flour mixture gradually for a smoother batter.
3. Stir in orange zest and juice, vanilla, grated carrot, and toasted nuts. Divide batter evenly into prepared cake pans, and bake at 375° for 40 minutes or until a knife inserted into center of cake comes out clean. (Layers may sink a bit in the middle.)
4. Let layers cool in pans 10 minutes; transfer to a cooling rack. Let cool completely. Top 1 layer with Cream Cheese Frosting; add second layer; frost top and sides of cake.
Store the finished cake in the refrigerator to keep the frosting from getting too soft.