Beginner: How to make a mirrored "recesses'' in a shape of a spheres into an object mesh? I am complete beginner and since I dont know how to properly ask the question, I am not having luck with googling it. I can show you what I mean with pictures.

I am trying to make an egg shape with spherical holes in its mesh, but cannot really figure it out. Reference picture of the "holes" is this:
The following method works better when the faces are evenly spaced quads


Add a sphere
Go to edit mode
Press "A" to select all faces
Press "I" once or twice
Scale the individual faces down
Press "E" to extrude all faces
Press "S" to scale the faces to the center
After scaling it towards the sphere center apply
Add a Subdivision Surface Modifier 


I just found a tutorial that has another nice method: https://www.youtube.com/watch?v=nJXsgan3Juc