Peel and finely chop the shallot. Dice the tomatoes and Granny Smith apples into small cubes. Chop the chives. Gently mix them together.
Tie the bundle of asparagus. Place the asparagus in boiling salted water and cook for 5 to 10 minutes. Check the cooking with a knife. Once cooked, remove the asparagus and place them gently in ice water to set the color. Drain and remove the strings.
Remove the water from the oysters, chop them, and mix them with the diced vegetables. Add lemon juice and a drizzle of olive oil, then season with fine salt and Espelette pepper.
Plate the dish: split the asparagus in half and fan them out on the plate. In the center, place the tartare using a ring mold. Toast two thin slices of bread and place them on top.
Finish the presentation by drizzling with olive oil and balsamic vinegar.