Return all the mushrooms and shallots to the pot over medium-high heat. Add the tomato paste, thyme, cumin, coriander, cinnamon, and allspice, and stir to combine. Cook just until fragrant, 1-2 minutes. Add 5 cups of water and the salt and pepper. Bring to a simmer and lower heat to medium. Cook, stirring occasionally, for 20 minutes. Stir in the baby spinach and cook just until wilted, 1-2 minutes.