If you cut off the tops where there are 2 leaves the plant will then grow 2 tops in the place of that 1 you cut off. When it starts to flower then trim it again this time cut off the 2 tops and it will turn into 4 tops. Then if you cut off the 4 tops it will turn into 8 tops. Any time it starts to flower trim off the tops.
This year I am using a solar dehydrato for all my herbs. Fresh Basil has a very strong aroma a 1 gallon basket of basil in the kitchen the aroma will just about take over the entire house in a few hours. After it has been dehydrated its aroma is not as strong as it was before but it is easy so store in the spice rack.
In the past I filled 1 gallon zip lock bags with Basil tops and froze them. They hold pretty much all the aroma and flavor when frozen. A year later they smelled and tasted about the same so I did not plant basil for 3 years. I have some frozen Basil that is 4 years old I think after 4 years it has finally lost some of its aroma and flavor.
The frozen basil is more like fresh picked from the garden while the dehydrated basil is more like what you buy at the grocery store only better.