- Crush the crackers coarsely and toast them dry in the pan for two minutes until they smell nutty. Tip out.
- Pasta on, water properly salted. Keep a mugful of the water.
- Slake the cornflour with cold water.
- Evaporated milk, 100 ml pasta water and the mustard into the pan at a bare simmer. Cornflour paste in, two minutes to thicken.
- Drained sweetcorn in, then off the heat the drained tuna, folded not stirred.
- Pasta through, loosened with pasta water. Crumbs over at the table.
The mustard is doing more than it looks: without cheese the sauce has no sharp note at all, and mustard supplies it.
Crumbs at the table, never stirred in: they go soft within a minute.
Serves 3.