Heat 1 tbsp olive oil in a deep casserole dish or saucepan. Add the celery and cook for 5 minutes, or until softened.
Add the beans with a pinch of salt and cook for 2-3 minutes more. Add the vegetable stock, bring to a gentle simmer, and cook for 5 minutes.
Meanwhile, put the chopped parsley, mint and basil in a small bowl with the grated garlic and olive oil. Stir to combine, adding a little more olive oil if needed. Set aside.
Add the chopped asparagus to the pan and simmer for 2 minutes, or until a vibrant green and just cooked through.
Serve the stew across two bowls and drizzle the garlic herb oil on top.