I have made a variety of stocks in my kitchen over the years. Throwing the stalks of vegetables and cobs of the corn are a painful part of vegetable cleaning. They make the vegetable what it is.
In a pressure cooker, add the olive oil. Add the bay leaves and alll the vegetables, stalk and cob.
Let them brown a bit, it should take about 10-12 minutes or so.
Add water and put the lid on. Let it whistle for 2 on high and 1 on medium-low. Turn off the gas and let the steam escape.
Open the lid and drain the liquid in a pot through a strain. Let the stock bubble for a while, say 10 minutes.
Season with salt and pepper. Let it cool down and store in an airtight glass jar for upto 20 days in a fridge.
I used this stock to make two soups. Minestrone and Dumpling soup.