Prepare spinach: If using fresh spinach: Cook in a dry skillet with a splash of water until wilted (2–3 min). Drain and squeeze out excess moisture, then chop. If using frozen spinach: Thaw completely and squeeze out as much water as possible. Set aside.
Sauté aromatics: Heat olive oil in a skillet over medium heat. Add shallot/onion and cook 3–4 minutes until soft. Add garlic and cook 30 seconds more.
Make the sauce: Stir in non-dairy creamer, umami seasoning, nutritional yeast (if using), and nutmeg. Whisk in cornstarch or flour and simmer for 2–3 minutes, stirring, until slightly thickened.
Combine and season: Stir in the cooked spinach. Mix well and heat through. Season with salt and pepper to taste.
Serve hot: Great as a side, on top of potatoes, or tucked into a wrap or savory pastry.
