Cut an avocado in half, remove and dicard the pit, and scoop the avocado flesh out of the shell with a spoon. Mash it up a little with a few drops of lemon juice and some pepper.
Meanwhile, open a tin of sardines. Finely dice a shallot. Take the sardines out of the oil they are packed in and pour the oil over the shallot. Let it sit for a few minutes at least, or an hour or two.
When the times comes, spread some of the avocado on a piece of toast (a biscotte is good). Lay a sardine or a sardine fillet over the avocado. Spoon on a little of the diced shallot that has soaked in sardine packing oil. Finally, squeeze on a few drops of lemon juice. Shake on a few drops of Tabasco sauce if you want.
Eat. Enjoy. Repeat.
CHM said in a comment that he mashes sardines together with unsalted butter and spreads that mixture on toast. That recipe is in the Larousse Gastronomique:
Beurre de sardines. — Piler 75 grammes de filets de sardines à l'huile. Ajouter 100 grammes de beurre. Passer au tamis fin.In English, take the contents of a tin of sardines packed in oil and mash it up in a mortar with a pestle. Add about 3 oz. of butter. Push the paste through a fine sieve.
S'emploie froid : pour hors-d'œuvre divers ; chaud : pour canapés, croûtes, croustades.
Serve cold as an hors-d'œuvre (on toasted bread or melba toast, I assume), or hot on canapés, toasted croutons, puff pastry.