How to Make It
Preheat oven to 350°. Beat butter with an electric mixer until creamy; gradually add 2 cups brown sugar, beating until light and fluffy. Add eggs, 1 at a time, beating until blended after each addition. Beat in zest and vanilla.
Stir together 2 1/2 cups flour and next 3 ingredients; add to butter mixture alternately with milk, beginning and ending with flour mixture. Stir pecans into batter. Divide batter evenly between 2 (12-cup) muffin pans coated with cooking spray.
Bake at 350° for 18 to 22 minutes or until a wooden pick inserted in center comes out clean.
Meanwhile, bring orange juice, lemon juice, and remaining 1/3 cup brown sugar to a boil in a small saucepan over medium heat. Boil until sugar is completely dissolved and syrup has thickened slightly (about 1 minute).
Pierce top of each muffin several times with a wooden pick, and brush warm syrup mixture over muffins. Sprinkle tops of muffins with turbinado sugar, if desired. Cool in pans on wire racks 10 minutes.