Where is the Battle Workshop?

I know about cooking a feast in your stronghold and creating 10 servings but I'm not doing raids that size so it's a waste.

I created those BBQ dishes that feeds 4 but I can't use it at all. It states:

Can be used only at the Battle Workshop. Summoned food disappears in 5m or if the summoner dies. The BBQ buff persists through death and is removed when leaving the area.