Preheat oven to 400 degrees.
In a small bowl add spinach, green onions, garlic powder, dried onion, salt, whipped cream cheese, and parmesan.
Slice the French bread lengthwise and place on a lined sheet, cut sides up. Spoon the spinach mixture evenly over the bread halves. Top with white cheddar cheese.
Bake for 15 minutes. Cut into 2 inch slices, and serve immediately.