Dice the onion, carrots, and celery so they cook evenly. Mince the garlic and have the tomato paste ready.

In a large pot, heat the olive oil and butter over medium heat. Add the diced onion, carrots, and celery. Cook for about 6–8 minutes until the onions are soft and slightly translucent. Stir often so nothing sticks.

Push the veggies to the side and add the garlic for 30 seconds until fragrant. Mix in the tomato paste and cook another 1–2 minutes to deepen the flavor.

Pour in the crushed tomatoes and stock. Stir in the bay leaf and dried basil. Bring to a gentle simmer and let cook 12–15 minutes so the flavors meld.

Remove the bay leaf. Use an immersion blender to puree until velvety. If using a regular blender, cool slightly and blend in batches. For an ultra-silky bisque, pass through a fine-mesh sieve back into the pot (optional).

Stir in the heavy cream and add sugar if the tomatoes are very acidic. Taste and season with salt and pepper. Keep warm on low while you make the grilled cheese croutons.

Butter one side of each bread slice. Sprinkle a tiny pinch of garlic powder or smoked paprika on the butter if you like. Place cheese between two slices (butter side out) and cook over medium heat in a skillet until golden and cheese is melted, about 2–3 minutes per side.

Let the grilled cheeses rest 1 minute, then cut into 1-inch cubes. If you’re making ahead, you can toast the cubes briefly in the oven to keep them crisp.

Ladle the bisque into bowls, add a handful of grilled cheese croutons on top, and finish with fresh basil and cracked pepper.