Wash and dry all produce. Halve, peel, and finely chop shallot. Halve lemon. Drain and rinse capers.

Heat a drizzle of olive oil in a medium pot over medium heat. Add half the shallot and cook until softened, 2-3 minutes, tossing. Stir in couscous, stock concentrate, 2 cups water, and a large pinch of salt. Bring to a boil, cover, and reduce heat. Gently simmer until tender, 10-12 minutes.

Heat a drizzle of olive oil in a large pan over medium heat. Add remaining shallot and cook until softened, 2-3 minutes. Add spinach and toss until wilted, 2-3 minutes. Season with salt and pepper. Remove pan from heat and cover to keep warm.

Heat a drizzle of olive oil in another large pan over medium-high heat. Season cod on all sides with salt and pepper. Add to pan and cook until nicely browned on surface, 2-3 minutes per side.

Add thyme and 2 TBSP butter to pan. Once melted, spoon butter over cod and thyme until cod is cooked through, about 1 minute. Add capers and a squeeze of lemon and gently shake the pan to distribute and warm through. Season sauce to taste with salt and pepper. Discard thyme.

Divide couscous between plates, then top with spinach and cod. Drizzle with sauce from pan and serve.