To make the tonnato sauce, empty the can of tuna into a blender with the garlic clove, juice of the lemon, egg yolks and mustard. Blend until you have a smooth paste and then drizzle in the oils, with the blender running all the way through. You should have a thick, rich emulsion. Season to taste with salt and pepper.

Prepare the vegetables and cut them in half lengthways.

Serve with a pot of tonnato sauce and dill for dunking.