Teatimelady, I don`t know which Orange Zucchini Muffin recipe you are using, but here is my recipe for Orange Zucchini Cake:
1 Cup softened margarine
2Tbs.grated orange rind
1/2 tsp.nutmeg
2C. brown sugar
Cream till light and fluffy then add one at a time
4 eggs
Add alternately with liquids:
3 C. floue
1 Tbs.baking pdr.
1/2 tsp. salt
Liquids? 1/4 C Grand Marinier (or 1/4c. orange juice concentrate in addition to the O.J. below)
1/4 C. orange juice concentate
Stir in 1 C. shredded unpeeled zuchini
Pour into greased and floured Bundt cake pan. Bake @ 350 degrees 55-60 min.