Pre-heat oven to 190°C/375°F. Grease a baking pan and set aside.
Slice the top off a red pepper, removing stem and seeds then rinse and pat dry.
Drain and flake a tin of tuna and mix with 1 tbsp of Dijon mustard.
If you find a tablspoon of Dijon Mustard is a little strong we suggest on mixing the tuna with 1/2 tbsp of Dijon mustard and 1/2 tbsp mayonnaise instead.
Add the mixture to the pepper and bake it on the pan until soft, about 25 minutes.