كتاب الأشربة
36  
The Book of Drinks
(21)
Chapter: It is permissible to eat soup, and it is recommended to eat squash, And for the people eating together to show preference to one another even if they are guests, so long as the host does not object to that
(21)
باب جَوَازِ أَكْلِ الْمَرَقِ وَاسْتِحْبَابِ أَكْلِ الْيَقْطِينِ وَإِيثَارِ أَهْلِ الْمَائِدَةِ بَعْضِهِمْ بَعْضًا وَإِنْ كَانُوا ضِيفَانًا إِذَا لَمْ يَكْرَهْ ذَلِكَ صَاحِبُ الطَّعَامِ
Sahih Muslim 2041 b

Anas b. Malik reported that a person invited Allah's Messenger (ﷺ) to a meal. I also went along with him. He brought soup containing pumpkin. Allah's 'messenger (ﷺ) ate that pumpkin with relish. He (Anas) said:

When I saw that I began to place it before him, and did not eat it (myself). Anas said: It was since then that pumpkin was always my favourite (food).
حَدَّثَنَا مُحَمَّدُ بْنُ الْعَلاَءِ أَبُو كُرَيْبٍ، حَدَّثَنَا أَبُو أُسَامَةَ، عَنْ سُلَيْمَانَ بْنِ الْمُغِيرَةِ، عَنْ ثَابِتٍ، عَنْ أَنَسٍ، قَالَ دَعَا رَسُولَ اللَّهِ صلى الله عليه وسلم رَجُلٌ فَانْطَلَقْتُ مَعَهُ فَجِيءَ بِمَرَقَةٍ فِيهَا دُبَّاءٌ فَجَعَلَ رَسُولُ اللَّهِ صلى الله عليه وسلم يَأْكُلُ مِنْ ذَلِكَ الدُّبَّاءِ وَيُعْجِبُهُ - قَالَ - فَلَمَّا رَأَيْتُ ذَلِكَ جَعَلْتُ أُلْقِيهِ إِلَيْهِ وَلاَ أَطْعَمُهُ ‏.‏ قَالَ فَقَالَ أَنَسٌ فَمَا زِلْتُ بَعْدُ يُعْجِبُنِي الدُّبَّاءُ ‏.‏
Reference : Sahih Muslim 2041b
In-book reference : Book 36, Hadith 200
USC-MSA web (English) reference : Book 23, Hadith 5068
  (deprecated numbering scheme)