Use thick-cut bacon if possible. Thinly sliced bacon will not have enough thickness to give you the textural contrast between the crisp exterior and the meaty interior of the lardons. If you can get extra thick-cut bacon, go for it! And, of course, you could thinly slice some regular-cut bacon and get skinnier little lardons, lighter and crisper in texture, and those will be mighty fine as well.