Up and down?

An eclair will, or should, contain lots of real cream, also, the pastry is more air than solid and is, or should be made with eggs and butter as well as flour. Your eclair may, therefore, have been less high carb than you might imagine and the carbs that were there may have been slowed down by the cream. if you had tested after two hours, the reading might have been higher.
Your Lidl roll will be solid carb and the hot dogs are not likely to have been much better and I expect the fat content will have been modest so all a sudden sugar rush.
Your results are not quite as surprising as they may seem on first sight. This isn't about diabetes kicking you in the teeth, it's about choosing your junk food wisely and learning by experience.
Sally

Don't forget BG levels are not always predictable.
The eclair indeed would have been *relatively* low in carbs and sugar. If I'm not mistaken about 12 g carbs. As explained in more detail above.
Your Lidl roll (presumably high protein) would have been 8 carbs with probably about 6 gr carbs total for the sausages. Plus a lot more protein than the eclair I expect.
All a case of trial and error!