Add the canola oil to a saucepan over medium-low heat. Cook the onions in the oil until soft.
Add the garlic, celery, and bell pepper to the saucepan. Cook an additional 3-4 minutes or until the vegetables are tender.
Using a wooden spoon, stir in the flour and cook for one minute.
Add the black pepper, bay leaf, and thyme to the saucepan.
Slowly pour in the stock and potatoes.
Stir thoroughly and cover. Simmer for 30 minutes.
Remove the bay leaf and add the corn and cayenne pepper.
Puree the soup in a blender or food processor until smooth.
Place the soup into bowls and garnish each with one chopped cherry tomato, one teaspoon sharp cheese, and two tablespoons shredded lettuce.