Melt the butter in a 4-quart saucepan. Add celery and onions.
Allow the onions and celery to cook for a few minutes until they turn semi-translucent.
Add the flour to the pan to make a roux.
Turn down the heat and allow the veggies and roux to cook for about 5 minutes, do not let the roux get too dark or burn.
Heat the stock in another saucepan.
Let the roux mixture cook for 5-7 minutes (the flour should begin to smell a little like bread) then add the stock to the roux, use a wire whip and mix well.
Add the tomatoes and seasonings and allow to simmer for about 30 minutes.
If you have an immersion blender after the bisque has simmered use your immersion blender to puree as much of the product as possible, you can also transfer it to a food processor or blender, just be very careful with the hot bisque.
After you have either used an immersion blender or food processor, strain your bisque to remove all the bits and pieces of celery, onions, and tomatoes.
Return the bisque to the pot and add the heavy cream and fold in the shredded cheddar.
At this time if the bisque appears to thick you can either add more vegetable stock, milk, or just plain water.
Taste the soup and re-season if necessary, then allow the soup to simmer over low heat for another 30 minutes. Serve and enjoy!