slap-up 
adjective [attributive] British informal
(Of a meal or celebration) large and sumptuous: a slap-up dinner...
- Last month, Hilary, 30, celebrated her second Oscar win with a slap-up meal - in a burger bar.
- ‘I was promised a slap-up meal and a few drinks on them the next time the missus and I go to the races,’ said Peter perking up at the prospect.
- It did mean I had to finish the cake, despite the fact I was full to the brim with a slap-up meal, red wine and champers, and felt a little like throwing up.
Synonyms
lavish, sumptuous, elaborate, expensive, no-expense-spared, fit for a king, princely;
excellent, splendid, magnificent, marvellous, superb, first-class