Put the goat cheese with the sour whipped cream, 2 tbsp olive oil and vinegar in a tall, slender container. Boil the whipped cream and pour it into the cheese. Blend everything with a hand blender to a smooth puree. Season with salt and pepper and set aside.
Remove the outer leaves from the lettuce and chop the stem a little. Rinse the lettuce hearts six times and thoroughly in cold water and then spin dry. Remove the tomatoes from the panicles and cut them in half. Unthread the celery and cut into very fine slices.
Cut the ciabatta bread into 6 slices and cut them in half lengthwise. Dip each bread slice briefly in the remaining oil and place on a baking sheet lined with parchment paper. Bake in the heated oven on the 2nd rack from the bottom at 200 degrees for 7-8 minutes (gas 3, convection oven 180 degrees ). After baking, season lightly with salt. 4.
Arrange the lettuce hearts on a platter. Divide tomato halves and celery evenly over the top and drizzle with half of the dressing. Season with enough pepper to taste. Serve the lettuce with the remaining dressing and crouetons.