Make sure you use a square pan even if you use your own recipe. It makes the slicing much easier.
Remove from the pan and let cool. Slice in about 3/4" to 1" strips.
Don't cut in squares yet. It is easier to toast this way.
Brush oil on a baking sheet.
Lay the strips of banana bread on the baking sheet with one of the cut sides down.
Brush more oil on the top of each strip.
Turn on your broiler and broil for 1 to 1 1/2 minutes until just golden brown.
Don't walk away. Check at 45 seconds and then at a minute. In the last few seconds they start to get very brown very quickly.
Remove from the oven and flip each strip over so that the other cut side is up.
Brush with oil again and lightly brown under the broiler as you did the other side. Remember don't walk away. It just takes seconds.
Take out of the oven an let cool. Cut into cubes.
The newly cut edges do not have to be toasted. The croutons will be crunchy enough as they are.
After they have cooled keep in an airtight container or zip lock bag and serve on fresh salads.