I'll offer a few suggestions - probably including JCFC's "easy" ones, and quite possibly including one or two which are erroneous....
1. Gobi (?)
9. Somali
12. Colorado (?)
15. Ice Cream
18. Arabian
20. Eton Mess
21. Spotted Dick
24. Atacama (?)
25. Kalahari
36. Death Valley
39 Apple Pie
45. Whip
48. Banbury Cakes
49. Pancakes
Hope you get some useful contributions from elsewhere!