Preheat oven to 350°F. Spray or rub oil into 8×8-inch baking dish.
Melt butter in a large saucepan. Remove from heat and stir in sugar and honey.
If using a fresh orange, grate the orange peel on the small or medium holes of a grater, taking off only the orange, outer layer (zest). Juice zested orange. Add more orange juice (fresh or bottled) to reach 3/4 cup.
Heat orange juice in the microwave about 30 seconds, or until warm but not hot. Stir orange juice into butter mixture, until smooth. NOTE: If you stir cold juice into the butter mixture, the butter will harden and form clumps. It’s also easier to dissolve sugar in warm liquid.
Mince ginger, if using.
Once butter mixture has cooled to lukewarm, add one egg at a time, beating lightly after each one.
Stir in optional fresh ginger and orange zest.
Add dry ingredients to the saucepan, then stir gently with a whisk (or kitchen spoon) just until incorporated. Don’t overmix.
Immediately pour batter into prepared baking dish, and bake for 35 minutes, or until done. Test by inserting a wooden toothpick in the center. It should come out clean. (Alternatively, press down lightly in the center. If it pops up, it’s done.)
Cool at least 10 minutes before cutting into squares.