When cooler weather arrives (or simply refuses to LEAVE) and you crave something deeply comforting, nothing hits quite like a steaming bowl of roasted tomato soup topped with crispy, cheesy croutons made from your favorite homemade sourdough. This recipe celebrates the rich, soul-satisfying flavors of our cheesy sourdough loaf — a simple variation of the soft sandwich loaf from our Ultimate Guide to Homemade Sourdough: Starter, Benefits & Soft Sandwich Loaf. Roasting whole onions with skins on delivers smoky caramelization, while a whole head of garlic roasted confit-style creates nutty, infused-oil richness. Sweet roasted tomatoes blend with subtle smoke and garlic depth, all crowned with golden, melty grilled cheese bites that soak up the broth perfectly while staying crisp in the center.
Perfect for chilly evenings curled up at home or sharing with loved ones — this is slow-roasted goodness that turns any day into something special. Let’s make it together.
Ingredients for the Roasted Tomato Soup
- 3 lbs (about 1.4 kg) ripe Roma or plum tomatoes, halved lengthwise (choose the best seasonal ones available)
- 2 large sweet onions, quartered (keep the papery skins on for extra depth)
- 1 whole head garlic
- 4–5 tablespoons extra-virgin olive oil, divided
- 2 teaspoons fine sea salt, divided
- 1 teaspoon freshly cracked black pepper
- ½ teaspoon smoked paprika (for that gentle smoky whisper)
- 2–3 sprigs fresh thyme (or 1 teaspoon dried)
- 4 cups (1 L) vegetable or chicken stock (homemade if possible, or low-sodium)
- 1 teaspoon balsamic vinegar (for bright balance)
- Optional: ¼ cup heavy cream or crème fraîche for silky finish
Ingredients for the Luxurious Grilled Cheese Croutons
(Using 2 thick slices of your cheesy sourdough loaf — see our full Ultimate Guide to Homemade Sourdough: Starter, Benefits & Soft Sandwich Loaf for the base recipe and cheesy variation)
- 2 thick slices (about ¾-inch) cheesy sourdough bread
- 2–3 teaspoons softened unsalted butter
- ½–¾ cup extra shredded old cheddar (or a mix of gruyère and parmesan for nutty luxury)
- Optional: pinch of smoked paprika or fresh thyme leaves for extra flair
Step-by-Step Instructions
1. Roast with Intention
Preheat your oven to 425°F (220°C). Line a large sheet pan with parchment paper for easy cleanup.
Place tomato halves cut-side up on the pan. Nestle the quartered onions (skins on!) among them — this is where the magic starts.
For the garlic: Slice off the top ¼ inch of the whole head to expose the cloves. Set it on a small foil square, drizzle with 1–2 tablespoons olive oil, sprinkle a pinch of salt, and seal into a tight packet.
Drizzle the tomatoes and onions with the remaining 3 tablespoons olive oil. Sprinkle 1½ teaspoons salt, black pepper, smoked paprika, and tuck thyme sprigs around everything. Toss gently to coat.
Place the garlic foil packet right on the pan. Roast 40–50 minutes, flipping the tomatoes halfway, until the tomatoes collapse and caramelize at the edges, onions turn deeply golden (skins will char for that smoky boost), and the garlic packet feels soft when pressed.
2. Extract Every Layer of Flavor
Cool for 5–10 minutes. Discard the charred onion skins — they’ve imparted gorgeous depth!
Squeeze the soft, roasted garlic cloves into a blender or large pot (they’ll pop out creamy and aromatic). Pour in the garlic-infused olive oil from the foil — this is your liquid gold!
Add the roasted tomatoes, onions, all pan juices, stock, balsamic vinegar, and remaining salt/pepper to taste. Blend in batches until velvety smooth.
3. Finish and Taste for Perfection
Transfer to a pot and warm gently over medium-low heat until steaming — avoid a hard boil to preserve the delicate flavors.
Taste and adjust: more salt, pepper, or a splash of balsamic for brightness. Off heat, swirl in cream or crème fraîche if desired for extra silkiness.
4. Crown with Grilled Cheese Croutons
While the soup warms, make the croutons:
Preheat oven to 375°F (190°C). Line a small sheet with parchment.
Butter both sides of each sourdough slice. Pile cheese thickly on one side, pressing gently. Add paprika or thyme if using.
Bake 8–12 minutes until bubbly, golden, and crisp-edged. Cool 2 minutes, then cut into rustic squares or triangles.
Float 4–6 croutons per bowl — they’ll soak up broth at the edges while staying delightfully crisp in the center.
Notes & Tips from The Coordinated Kitchen
- Those onion skins and garlic-infused oil? They’re the game-changers — adding smoky, nutty layers that make this soup taste restaurant-worthy.
- Texture tweaks: Too thick? Splash in more stock. Too thin? Simmer uncovered 5–10 minutes to concentrate.
- Make-ahead magic: The soup freezes beautifully (skip cream before freezing). Re-crisp croutons in a 350°F oven for 3–4 minutes.
- First spoonful ritual: Close your eyes, inhale that roasted tomato sweetness mixed with smoky onion and garlic richness, then savour the salty-cheesy sourdough crunch. This is comfort you can taste folks.
Pair this with a crisp green salad or just a quiet moment of pure bliss, whilst you sit by the window staring at the snow, yes still snow in March! Where art thou spring & more importantly… why haven’t you sprung?!
All my love and wishes for warmer weather,
Your forever kitchen cheerleader at thecoordinatedcook.com 🥖🍅🧀💛
