Big Mama Makes the World by Phyllis Root, illustrated by Helen Oxenbury

From chapters.ca:
When Big Mama made the world, she didn't mess about. Earth sky and sea, sun and moon, plants and trees, fish, birds and animals all fell right in line with Big Mama's plans. What Big Mama wants, Big Mama gets. That's how it is. It wasn't easy, either, with that little baby to take care of. But nothing stops Big Mama. Not for a second. Through it all - from darkness to light, from far up in the clouds to the bottom of the ocean, from a ball of mud to a big bang - shines Big Mama, larger- than- life and down- to- earth, with her baby sitting on her hip and the laundry piling up.