Creamy Tomato Basil Soup

Why This Is Strictly Keto

Traditional tomato soup often leans on added sugar to balance the tomatoes’ acidity — this version uses a touch of erythritol instead, along with mascarpone and butter for its creaminess rather than a flour-based roux. No sugar, no flour, no cream-of-tomato-soup shortcuts.

Ingredients

• 1 can (28 oz) whole peeled plum tomatoes (San Marzano if available)
• 2 cups filtered water
• 1½ teaspoons coarse kosher salt
• ½ teaspoon onion powder
• ¼ teaspoon garlic powder
• 1 tablespoon butter
• 8 oz mascarpone cheese
• 2 tablespoons granulated erythritol
• 1 teaspoon apple cider vinegar
• ¼ teaspoon dried basil
• ¼ cup prepared basil pesto, plus extra for garnish
• Fresh basil leaves, for garnish

Instructions

1. Simmer the tomatoes: Combine the canned tomatoes, water, salt, onion powder, and garlic powder in a medium saucepan. Bring to a boil over medium-high heat, then reduce heat and simmer for 2 minutes.

2. Purée: Remove from heat and purée with an immersion blender until completely smooth.

3. Add the creamy base: Return the pan to the stove over low heat. Add the butter and mascarpone cheese, stirring until fully melted and incorporated, about 2 minutes.

4. Season: Remove from heat and stir in the erythritol, apple cider vinegar, dried basil, and basil pesto. Taste and adjust salt or sweetener as needed.

5. Serve warm, topped with a swirl of extra pesto and fresh basil leaves.

Nutritional Info (per serving, approximate)

Tips

• An immersion blender lets you purée directly in the pot — far less cleanup than a stand blender.
• Mascarpone gives a milder, silkier finish than cream cheese; full-fat cream cheese can be substituted in a pinch.
• Leftovers keep well refrigerated up to 5 days, or frozen up to 3 months — the mascarpone base holds up better to freezing than milk-based tomato soups.