Cook quinoa according to the instructions on the packaging.
Heat the butter in a medium-sized saucepan with a lid over medium heat. When hot, add the chopped garlic and cook until fragrant, about one minute. Do not burn.
Add in the cooked quinoa and mix until the quinoa is covered in the garlic butter mixture. Cook until the mixture is just heated through.
Add in the baby spinach, lemon juice, and lemon zest, and stir through until the spinach is just wilted. Remove from the heat.
Season with salt and pepper to taste and serve.
