Rayner summed up the restaurant at the hotel near Ripon as 'confused and asphyxiatingly expensive' and was impressed only with the desserts.
However he found prices too high and criticised the food's presentation.
Fletchers has appeared in the Michelin Guide before and is one of eight food and drink venues at the hotel, which was restored by businesswoman Valeria Sykes and opened in 2019.
Rayner was scathing of the dining room's Scottish baronial-style decor and the 'excesses of the overly moneyed' he deemed to be on show and described the five-star hotel as 'hilariously over the top'.
He quotes prices including a chicken and avocado salad for £21 and a smoked salmon sandwich platter for £16.50, and calls many dishes 'exhaustingly fussy'. Rayner even says the chips remind him of frozen ones.
He does, however, compliment the cooking of the pigeon breast and is enthusiastic about the desserts, which he calls 'some of the best examples of detailed patisserie work it has been my pleasure to experience in a long time' and 'dishes that feel like they are from an entirely different restaurant'.
The bill for him and his companion came to £150 without wine.