Preheat oven to 350 degrees F; prepare a bundt cake pan with nonstick spray and set aside.
Sift flour, baking powder, baking soda, salt, cinnamon and nutmeg together and set aside.
In a large bowl, use an electric mixer to mix sugars, eggs, orange juice, orange zest, buttermilk, honey, vanilla extract, and tea until well blended, approximately 2 minutes.
Slowly add the dry ingredients, mixing well to incorporate after each addition; when all dry ingredients are added, mix for an additional 3 minutes.
Fold walnuts into cake batter and pour into prepared cake pan.
Bake for 45 minutes to 1 hour, or until a cake tester inserted into the center of the cake comes out clean.
Allow cake to cool completely before serving.