Not the name of a tavern, but an un-named tavern that had a grotto of some kind.
18 Apr 2011, 3:43 a.m. - Terry Foreman
"Kensington, like other villages along main roads out of London, long attracted hostelries and drinking houses for travellers; Pepys, for one, confides to his diaries of the 1660s the record of several expeditions to Kensington and bibulous evenings in one or more taverns there (one with a grotto, but all unnamed).2. The Diary of Samuel Pepys, edd. Robert Latham and William Matthews, vol. 5, 1971, pp. 178, 180–1; vol. 9,1976, pp. 166, 170, 203."
19 Apr 2021, 3:36 a.m. - San Diego Sarah
It's curious to note that the two times Pepys went to the Grotto, he records having a good time singing, and there being fine company. And both times it was without Elizabeth. And both times he mentions being in the company of Edward Rold / Rolt.
Chart showing the number of references in each month of the diary’s entries.