According to Wikipedia, "The pastry resembles a doughnut and is made from croissant-like dough which is filled with flavored cream and fried in grapeseed oil."
The Shulchan Aruch (O.C. 168:13) rules:
אפילו דבר שבלילתו (פירוש לישת הקמח במים) עבה אם בשלו או טגנו אין מברך עליה המוציא אפי' שיש עליה תוריתא דנהמא ואפי' נתחייב' בחלה דברכת המוציא אינו הולך אלא אחר שעת אפייה ויש חולקין ואומרי' דכל שתחל' העיסה עבה ואפי' ריככה אח"כ במים ועשאה סופגנין [פי' עיסה שלשוה ועשאה כמין ספוג] ובשלה במים או טיגנה בשמן מברך עליהם המוציא ונהגו להקל וירא שמים יצא ידי שניה' ולא יאכל אלא ע"י שיברך על לחם אחר תחל': הגה כל זה לא מיירי אלא בדאית ביה לאחר אפייה תואר לחם [ל' הטור והפוסקים] אבל אי לית ביה תואר לחם כגון לאקשי"ן שקורין בל"א ורימזלי"ך לכ"ע אין מברכין עליהם המוציא ולא ג' ברכו' דלא מיקרי לחם אבל פשטיד"א וקרעפליך מקרי תואר לחם (מרדכי פ' כל שעה) ואין לאכלם אא"כ בירך על שאר הפת תחלה וכל זה לא מיירי אלא בעיסה שאין בה שמן ודבש וכיוצא בו אלא שמטוגן בהם אבל אם נילוש בהם כבר נתבאר דינו אצל פת הבא' בכסנין
There are two opinions about the bracha on dough which is fried. The main opinion is that it never gets the bracha of hamotzei; this opinion says that bread by definition must be baked. This is the main opinion in the Shulchan Aruch, and the Rema says that the custom is to follow this opinion.
The second opinion brought posits that any regular dough (as opposed to a batter) would require hamotzei and birkas hamazon.
The Shulchan Aruch only says that a "yirei Shomayim" (a G-d fearing person) should be strict and eat fried dough during a meal, to avoid the doubt. It seems clear that his main ruling is also to be lenient. (I recall a teshuva from a sefardi gadol- perhaps Ohr Letzion?- who brings a proof from hilchos challah that the Shulchan Aruch is not really concerned about this strict opinion, and thus even Sefardim can be lenient. I'll edit this when I can find the source.)
In addition, the Rama adds two very important conditions.
Even the strict opinion requires that the fried (or boiled) dough maintain "toar lechem" the appearance of bread. So noodles are always mezonos, since they are not bread.
The strict opinion is talking about regular fried dough consisting of flour and water. If there are other ingredients added, such as oils eggs or sugar, it would at most go back to the previously discussed topic of pas habah bakisnin (O.C. 168: 6-8).
There, the ruling would be that the bracha in mezonos unless a person "establishes his meal upon it" (see there with the commentaries, who discuss if it's a question of a certain volume or of eating a quantity most people would consume for their normal meal.
(See here and here for more discussion.)
In summary:
-According to the main Ashkenazi custom, these fried (sweet and oil-filled) cronuts are always mezonos no matter how many you eat.
- According to the normative Sefardi halacha the bracha is the same.
- For a "Yirei Shomayim"- a G-d fearing person- there might be room to be strict and only eat it after making hamotzei on real bread if:
- Cronuts are determined to still have "the appearance of bread"
- One eats a large enough quantity to establish one's meal over the cronut.
There seems to be no situation where one should actually make "hamotzi" over the cronut.
On a final note:
I heard a talk from Rav Berel Wein shlita and he quoted a shaila which was brought to Rav Moshe Feinstein zatza"l. As is known, Rav Moshe was lenient about milk under government supervision (see the discussion here) but a "baal nefesh", someone cautious about his spirituality, would be stringent.
So someone came to Rav Moshe and asked him if eating milk chocolate, which contained "chalav stam" milk (powder), was appropriate for a "baal nefesh."
Rav Moshe responded, "If you're eating chocolate, you're probably not a baal nefesh!"
I think that might apply here as well- is eating so many cronuts in a DD that there's a question of "establishing one's meal," in line with being a "yirei shomayim" who should be concerned with that minority opinion...?