Toast pecans in a single layer on a baking sheet for 8 to 10 minutes at 350, stirring once. Meanwhile beat sugar and butter at medium speed with an electric mixer until blended. Add eggs one at a time beating after each addition. In a small bowl, whisk the sweet potatoes, orange juice, and vanilla. In a separate bowl, whisk flour, baking powder, cinnamon, baking soda, nutmeg, ginger and salt. Slowly add the flour mixture to the butter mixture, beat after each addition. Alternate the flour mixture addition with the sweet potato mixture. Fold in toasted pecans. Place baking cups in muffin pans, coat with cooking spray. Using an ice cream scooper, scoop batter into cups. Bake at 350 degrees for 28 to 30 minutes or until a toothpick inserted into the middle comes out clean. Cool completely before adding frosting.