How to disable the "Hot on Google+" feature in the new G+ layout:
Look at the side bar on the left. You'll see an icon that says "Explore". It looks like a compass.
Clicking on it will take you to another page.
On the new page there will be a slider bar somewhere near the middle of the screen. You may possibly need to scroll down in order to see it.
This slider bar will adjust how much of the "Hot on Google+" content will show up in your news feed. To disable this feature just move the slider all the way to the left.
Enjoy an improved G+ experience!