Heat the butter in a medium saucepan over medium-high heat.
When foaming subsides, add shallots and cook, stirring frequently, until softened and lightly browned, about 5 minutes.
Add garlic and cook until fragrant, about 30 seconds.
Add couscous and cook, stirring frequently, until grains are just beginning to brown, about 5 minutes.
Add water, broth, and salt; stir briefly to combine, cover, and remove pan from heat. Let stand until grains are tender, about 7 minutes.
Uncover and fluff grains with a fork.
Stir in almonds, parsley, lemon juice, and zest, season with pepper to taste, and serve.