Start by peeling and dicing the potatoes into roughly 1-inch cubes. Finely dice the onion and mince the garlic cloves.
Heat the olive oil in a large heavy-bottomed pot over medium heat until shimmering. Add the diced onion and sauté for about 5 minutes, until it turns translucent and begins to soften, filling the kitchen with a gentle aroma.
Add the minced garlic to the pot and cook for about 1 minute, stirring constantly until fragrant and slightly golden—this boosts the garlic's sweet, toasty aroma.
Toss in the diced potatoes, stirring well to coat them with the onion and garlic mixture. Cook for 2 minutes, allowing the potatoes to start absorbing the flavors.
Pour in the vegetable broth, bringing the mixture to a gentle boil. Once bubbling, reduce the heat to low and cover the pot.
Let the soup simmer gently for 15-20 minutes, until the potatoes are very tender and easily pierced with a fork, filling the kitchen with a comforting, starchy aroma.
Remove the pot from heat and carefully blend the soup using an immersion blender until smooth and velvety. Alternatively, transfer in batches to a blender, blending until silky, and return to the pot.
Stir in the nutritional yeast, fresh thyme, and season generously with salt and pepper. If the soup feels too thick, add a splash of hot broth or water to loosen it to your preferred consistency.
Taste the soup and adjust the seasoning as needed. For an extra bright note, stir in the lemon juice just before serving.
Serve the hot, creamy soup in bowls, garnished with a drizzle of olive oil or fresh herbs if desired. Enjoy this cozy, nourishing dish on a chilly day!
