A silky, vibrant-green pea soup with sweet, fresh pea flavor, fragrant thyme, and creamy body from potato—entirely dairy-free and delicious served hot or chilled.
Warm the olive oil in a large pot over medium-high heat.
Add the diced onion and sauté until translucent, about 3 minutes.
Stir in the minced garlic, dried thyme, and fine sea salt; cook, stirring constantly, until fragrant, about 1 minute.
Pour in the vegetable broth and stir in the grated potato. Cover with the lid slightly ajar and bring to a boil.
Boil until the potato is soft, about 10 minutes.
Add the frozen peas and cook until bright green and heated through, 2 to 3 minutes; remove from heat.
Stir in the baby spinach (if using) until wilted.
Blend the soup until smooth using an immersion blender, or carefully in batches in a countertop blender.
Season with black pepper and additional salt to taste. Garnish as desired and serve hot or chilled.