Quick Recipe Version (TL;DR)
Quick Ingredients
- 3 lb (1.36 kg) Roma tomatoes, halved lengthwise
- 1 large yellow onion, cut into 8 wedges
- 6 garlic cloves, peeled
- 3 tbsp olive oil
- 1 1/2 tsp kosher salt, divided
- 1/2 tsp freshly ground black pepper
- 3 cups (720 ml) low-sodium vegetable broth (or chicken broth)
- 2 tbsp tomato paste
- 1 tsp granulated sugar (optional)
- 2 tbsp balsamic vinegar
- 1/2 cup (120 ml) heavy cream (optional, for a velvety finish)
- 8 slices sourdough bread
- 6 tbsp (85 g) unsalted butter, softened
- 8 oz (225 g) sharp cheddar cheese, shredded
- 4 oz (115 g) low-moisture mozzarella, shredded
- Optional garnish: 1/4 cup basil leaves, torn
Do This
- 1) Heat oven to 425°F (220°C). Toss tomatoes, onion, and garlic with 2 tbsp oil, 1 tsp salt, and pepper on a sheet pan.
- 2) Roast 35 minutes until tomatoes slump and edges caramelize.
- 3) Blend roasted veg with broth, tomato paste, balsamic, and sugar (if using) until smooth.
- 4) Simmer 10 minutes; stir in cream (optional) and adjust salt to taste.
- 5) Butter bread; fill with cheddar + mozzarella. Grill in a skillet over medium-low heat 4–6 minutes per side.
- 6) Serve hot soup with basil and a grilled cheese for dipping.
Why You’ll Love This Recipe
- Roasting concentrates the tomato flavor and adds a gentle sweetness with caramelized edges.
- The soup turns silky and velvety in minutes (blender does the heavy lifting).
- Classic grilled cheese with a two-cheese blend gives you maximum melt and stretch.
- Simple ingredients, big comfort-food payoff.
Grocery List
- Produce: 3 lb Roma tomatoes, 1 large yellow onion, 6 garlic cloves, fresh basil (optional)
- Dairy: unsalted butter, sharp cheddar cheese, low-moisture mozzarella, heavy cream (optional)
- Pantry: olive oil, low-sodium vegetable broth (or chicken broth), tomato paste, balsamic vinegar, granulated sugar (optional), kosher salt, black pepper, sourdough bread
Full Ingredients
Oven-Roasted Tomato Soup
- Roma tomatoes: 3 lb (1.36 kg), halved lengthwise
- Yellow onion: 1 large, cut into 8 wedges (keep the root end intact if possible so wedges hold together)
- Garlic: 6 cloves, peeled
- Olive oil: 3 tbsp, divided
- Kosher salt: 1 1/2 tsp, divided (plus more to taste)
- Black pepper: 1/2 tsp
- Tomato paste: 2 tbsp
- Low-sodium vegetable broth (or chicken broth): 3 cups (720 ml)
- Balsamic vinegar: 2 tbsp
- Granulated sugar (optional): 1 tsp (helps if your tomatoes are very acidic)
- Heavy cream (optional): 1/2 cup (120 ml)
Grilled Cheese
- Sourdough bread: 8 slices (about 1/2 in / 1.25 cm thick)
- Unsalted butter: 6 tbsp (85 g), softened
- Sharp cheddar: 8 oz (225 g), shredded
- Low-moisture mozzarella: 4 oz (115 g), shredded
Optional Garnishes (Highly Recommended)
- Fresh basil: 1/4 cup, torn or thinly sliced
- Extra cream: 1–2 tbsp for swirling on top
- Black pepper: a few extra cracks right before serving
Step-by-Step Instructions
Step 1: Preheat the oven and prep the pan
Place a rack in the center of the oven and preheat to 425°F (220°C). Line a large rimmed sheet pan with parchment paper for easier cleanup (optional, but helpful).
Set out a blender (standard blender works best for the smoothest texture). If you’ll be using an immersion blender, plan to blend the soup in a pot later.
Step 2: Roast the tomatoes, onions, and garlic
Add the halved tomatoes (cut-side up), onion wedges, and peeled garlic cloves to the sheet pan. Drizzle with 2 tbsp olive oil, then sprinkle with 1 tsp kosher salt and 1/2 tsp black pepper.
Roast for 35 minutes, until the tomatoes are collapsed and jammy, the onions are tender, and you see caramelized, browned edges on the tomatoes. (Those browned bits are flavor.)
Remove the pan from the oven and let it cool for 5 minutes so blending is safer and easier.
Step 3: Blend the soup until silky
Carefully transfer the roasted tomatoes, onions, garlic, and any juices from the pan into a blender. Add the tomato paste, 3 cups (720 ml) broth, 2 tbsp balsamic vinegar, and 1 tsp sugar (if using).
Blend until very smooth, 30–60 seconds. If your blender has a vented lid, open it slightly and cover with a kitchen towel to let steam escape. If not, blend in smaller batches to avoid pressure buildup.
Step 4: Simmer and finish for a velvety texture
Pour the blended soup into a medium pot or Dutch oven. Bring to a gentle simmer over medium heat, then reduce to medium-low and simmer for 10 minutes, stirring occasionally.
Stir in the remaining 1 tbsp olive oil and the 1/2 cup (120 ml) heavy cream (if using). Taste and adjust with up to 1/2 tsp more kosher salt if needed.
Keep warm on low while you make the grilled cheese.
Step 5: Assemble the grilled cheese sandwiches
In a small bowl, toss together the shredded cheddar and shredded mozzarella so each sandwich gets a good mix of sharp flavor and melty stretch.
Butter one side of each bread slice with softened butter (use about 3/4 tbsp per slice; you’ll use a total of 6 tbsp). Build 4 sandwiches: place 4 slices bread butter-side down, mound the cheese evenly across them, then top with the remaining bread slices butter-side up.
Step 6: Grill slowly for crisp bread and fully melted cheese
Heat a large skillet or griddle over medium-low heat. Add 1–2 sandwiches (don’t overcrowd). Cook for 4–6 minutes on the first side, until deeply golden brown. Flip and cook 4–6 minutes on the second side.
If the bread is browning too fast before the cheese melts, lower the heat to low and cover the skillet for 1–2 minutes to help the cheese melt through.
Transfer to a cutting board and rest for 1 minute, then slice in half.
Step 7: Serve hot with simple garnishes
Ladle the hot roasted tomato soup into bowls. If you’d like, swirl a small amount of cream on top and add torn basil. Serve immediately with grilled cheese on the side (or perched right on the rim of the bowl for easy dunking).
Pro Tips
- Use Roma tomatoes for a thicker soup: They’re less watery than many slicing tomatoes, which helps the soup stay rich and not thin.
- Don’t skip the roasting time: The soup’s deep flavor comes from caramelization. If your tomatoes look pale at 35 minutes, roast 5–10 minutes longer.
- Blend thoroughly: For truly velvety soup, blend a full 60 seconds (in a strong blender) and then simmer.
- Grilled cheese loves low heat: Medium-low gives the cheese time to melt before the bread gets too dark.
- Adjust acidity at the end: If it tastes a bit sharp, add the optional sugar (or another 1–2 tsp cream). If it tastes flat, add another 1 tsp balsamic vinegar.
Variations
- Roasted red pepper tomato soup: Add 1 large red bell pepper, seeded and quartered, to the sheet pan. Blend it in with the tomatoes for a smoky-sweet twist.
- Spicy tomato soup: Add 1/4 tsp crushed red pepper flakes to the roasting pan, or blend in 1–2 tsp adobo sauce from canned chipotles.
- Pesto grilled cheese: Spread 1 tbsp basil pesto inside each sandwich before adding cheese.
Storage & Make-Ahead
Soup: Cool completely, then refrigerate in an airtight container for up to 4 days. Reheat gently over medium-low heat, stirring occasionally. The soup also freezes well for up to 3 months; thaw overnight in the fridge before reheating.
Make-ahead option: Roast the tomatoes, onions, and garlic up to 2 days ahead. Refrigerate, then blend and simmer when you’re ready to eat.
Grilled cheese: Best fresh. You can shred the cheeses up to 3 days ahead and keep them refrigerated in a sealed container to make sandwich assembly fast.
Nutrition (per serving)
Approximate, per 1 serving (1/4 of soup + 1 grilled cheese sandwich): Calories: 780; Protein: 26 g; Carbohydrates: 58 g; Fat: 50 g; Fiber: 6 g; Sugars: 14 g; Sodium: 1250 mg.
