Roasted Plum Tomato Soup Recipe

Preheat and prepare

Preheat oven to 425°F (220°C). Line a rimmed baking sheet with parchment paper or lightly oil it.

Halve and season tomatoes

Wash the plum tomatoes and halve them lengthwise. Place cut-side up on the prepared baking sheet. Drizzle 2 tablespoons olive oil over the tomatoes, scatter the thyme sprigs, and sprinkle 3/4 teaspoon kosher salt and 3/4 teaspoon cracked black pepper (reserve the rest for the pan).

Prepare garlic and onion for roasting

Peel the garlic cloves (leave whole) and cut the onion into 1/2-inch wedges. Toss the garlic and onion wedges with the remaining 1 tablespoon olive oil and add to the baking sheet among the tomatoes.

Roast

Roast for 25–30 minutes, until the tomato edges are caramelized and slightly collapsed and the garlic is soft. If tomatoes are small, check at 20 minutes. Remove thyme stems after roasting (leave the leaves). Let cool slightly.

Sauté base (optional step for deeper flavor)

In a large saucepan or Dutch oven, melt the butter over medium heat (or use 1 tablespoon olive oil if you omitted butter). Add the roasted onion wedges (reserve tomatoes for later) and cook 2–3 minutes to develop flavor. Scrape any fond from the roasting pan with a splash of broth and add to the pot.

Add roasted ingredients

Add the roasted tomatoes, soft roasted garlic (squeeze from skins), and any collected juices from the baking sheet into the pot.

Add liquids and simmer

Stir in the vegetable broth, tomato paste, and sugar. Bring to a gentle simmer over medium heat, then reduce heat to low and simmer 10–12 minutes to let flavors meld.

Blend until smooth

Remove thyme stems. Use an immersion blender directly in the pot and blend until smooth and velvety, about 1–2 minutes. Alternatively, carefully transfer soup in batches to a blender and puree, then return to the pot.

Finish and adjust seasoning

Stir in the heavy cream (if using) and torn basil leaves. Warm through for 1–2 minutes without boiling. Taste and adjust seasoning with additional salt, cracked black pepper, and a pinch of red pepper flakes if desired.

Ladle soup into bowls. Top with croutons or grilled bread, extra basil leaves, and a light drizzle of olive oil. Serve warm.