Parenting can take you -10-15 minutes a day! 
If someone would have told me that I only have 15 minutes every day with each one of my children.
I would choose to spend this time on one thing: read them aloud books.

Because, when you read your child- a book,  
All the essence of being a  parent – exists:

You are reading a book – that represents some kind of the reality, the real world.
You experience this reality close physically
You can read and your children cannot read sometimes- so you are showing this reality to your child.
your child can ask you anything, can tell you their thought's, can be afraid or puzzled- and during this time -
You are there to: calm, explain, laugh, debate, and walk through it with your child.
You are not a teacher, and please don't turn this to a grammar or reading lesson.
Remember to use this unique  time, that happens only for several year's, to bond with your child.
Isn't that, the essence of...