Does anyone know where the icon for the Brisk Menu is stored and/or how to change it? It was easy enough with the Advanced Menu, but as that seems to be completely broken in 17.10, I thought I’d give it a try.
The Gnome footprint is cute, but I have a system of themes across my network for consistency (started out of boredom after I retired) and it just doesn’t fit.
Any help would be appreciated.
It changes according to the icon theme you are using, the file “start-here-symbolic” more specifically. To change it just place the icon file you wanna use (.svg or .png) to overwrite the existing one on the icon theme you are currently using.
Better to rename the old one first so you don’t lose it.
Check these links for more details:
http://antechdesigns.esy.es/change-start-button-in-brisk-menu/
Are you sure of this? That’s what I assumed but if I change the Gtk theme while keeping the icon theme, the Brisk menu icon changes too…
What do you mean by changing the gtk theme, you mean changing the Controls and Window Border? These do not change Brisk Menu's icon:
Or do you mean changing the theme here:
If you change it here I believe it changes Controls, Window Border and Icons, maybe even mouse pointer. So probably it will load a different icon set and consequently Brisk Menu's icon will also change.
I always use Custom theme and customize everything by hand, specially because most items are not complete and are only gtk window borders or only icons. So it's better to customize so you can choose each one you wanna use. In example at the moment I'm using Marcha-dark-aliz for Controls, Ambient-MATE for Window Border and Obsidian-Gray for Icons.
Got them all here: https://www.mate-look.org/
Yes. I do not use the Brisk menu usually and noticed this today when testing things: with my Gtk theme (a Numix variant), the Brisk menu displays the GNOME (foot) logo and I still use the Ambiant-MATE icon theme. I switch back to the Ambiant-MATE Gtk theme and I got the MATE logo back on the Brisk menu.
I agree it’s weird, as it should use a logo from the selected icon theme without anything else mattering and indeed, after a quick check, the start-here-symbolic icon in Ambiant-MATE is the GNOME foot logo. So, it looks like it uses it. What is unexpected is that when using the combination of Ambiant-MATE Gtk+icon themes, it uses a different icon. Not sure why/how.
So, while replacing start-here-symbolic in the icon theme would likely work in most cases, I don’t think it’s the proper way to set it. Looking at the files installed by Brisk, there seems to be DBus stuff, so I wonder if it uses settings in Dconf/Gconf to choose the icon depending of the Gtk or the global theme used.
If you change it here I believe it changes Controls, Window Border and Icons, maybe even mouse pointer.
That’s absolutely right. The global theme files define the Gtk + icons + Metacity + cursor themes to use. In my case, I use a custom global theme that sets a Numix variant as Gtk + Metacity, Ambiant-MATE for the icons and the MATE cursor.
You are heading into a mine field 
Using dconf you usually get two entries related to Brisk menu:
/com/solus-project/brisk-menu/and the entry for the panel:
/org/mate/panel/objects/object-1/note: it can be object 0, 2 or whatever according to the objects you have on your panel(s)
In the last one indeed you have the option to set a custom icon and to set the path for that icon, but… guess what, it does not work. 
For what I tested and similar to changing Brisk menu normal menu layout to the fullscreen layout (dash), it only works if you set it, delete the menu and add it again to the panel; but with the custom icon, being it in a panel object entry, as you delete the panel object so the custom item setting goes away.
I just wish they would add a setting to just change the icon easily.
Thanks @pemartins. I may give it a try, though I have since just decided to stick with the good 'ole Advanced Menu.
Go with clessley method.I have used his way for about a week and a half with absolutely no negative system issues.
Link rot; tutorial is now here: https://gripfastistech.com/index.php/blog/66-how-to-change-the-brisk-menu-icon-in-ubuntu-mate-18-04.html
TLDR; change the /usr/share/icons/Adwaita/places/start-here-symbolic.png that most closely matches your panel size, e.g. 4848, 64x64, etc.