Chocolate Orange Swirl Bread

I made this delicious bread for the kids' breakfast a couple days ago and it was a huge hit! I substituted clementines for the oranges, since that's what I had on hand, and made up the remaining amount with lemon juice. It was still great! Give it a try and let me know what you think!

Chocolate Orange Swirl Bread
(makes 2 loaves)

1 c. softened butter
2 c. sugar
4 eggs
2 lg. oranges
4 c. flour
4 tsp. baking powder
1 tsp. salt
2 TB. unsweetened cocoa
2 TB. milk

Mix butter, sugar, and eggs until well combined. Grate the peels from both the oranges to measure at least 2 TB. zest. Juice both oranges to equal approximately 1 c. of juice. If you don't get quite enough, you can add milk or water to make up the difference. Mix zest and juice into butter mixture. Mix flour, baking powder, and salt in a separate bowl, then stir into wet mixture until just combined. Pour all but 1 c. of mixture into 2 pans. Add cocoa and milk to the remaining mixture and whisk until well combined. Divide between the two pans, pouring down the middle of each. Use a knife to swirl the mixture around a bit. Bake at 325º for 1 hour.