Prepare the vegetables. Peel and dice the potatoes. Slice and thoroughly rinse the leek, dice the onion and tomatoes, slice the mushrooms, and mince the garlic.

Heat the olive oil in a large pot over medium heat. Add the onion, leek, and a small pinch of salt. Cook for 5 to 6 minutes, stirring occasionally, until softened.

Add the mushrooms and cook for 3 to 4 minutes. Stir in the garlic, turmeric, paprika, thyme, and black pepper. Cook for 30 seconds while stirring.

Add the diced potatoes and tomatoes. Pour in the vegetable broth and stir well.

Bring the soup to a gentle boil. Reduce the heat, partially cover the pot, and simmer for 18 to 22 minutes, until the potatoes are completely tender.

Remove the pot from the heat. Carefully blend the soup with an immersion blender until smooth. If using a countertop blender, allow the soup to cool slightly and blend it in small batches according to the manufacturer’s instructions.

Return the soup to low heat. Stir in the milk, half-and-half, cream, or unsweetened oat milk. Add the lemon juice and season with salt to taste. Warm gently for 2 to 3 minutes without boiling rapidly.

Divide the soup between four bowls. Garnish with parsley or chives and an optional swirl of cream. Serve warm with whole-grain or seeded bread.