Keto Silky Garlic Soup with Crispy Gruyère Toast
A luxurious French-inspired soup where caramelized onions and roasted garlic meld into a velvety base, finished with egg yolk and cream for richness. Topped with buttery sourdough crisps draped in melted Gruyère, this is comfort food with sophistication. Serve as an elegant first course in autumn or winter, or as a light supper alongside a salad. The tempering technique ensures the eggs create silkiness without scrambling, setting this version apart from simpler garlic soups.
Ingredients
- 1 tablespoon unsalted butter
- 4 ½ cups onions, chopped
- 1 cup garlic, sliced
- 8 cups chicken broth
- 1 ¼ teaspoons kosher salt
- ¼ teaspoon black pepper, freshly ground
- 5 large egg yolks
- 1 cup heavy cream
- 8 slices sourdough bread, or baguette
- 3 tablespoons butter, melted
- 2 cloves garlic, halved
- 1 ¾ cups Gruyère cheese, shredded
Instructions
- 1
Melt butter in a large sauce pan over medium-low heat.
- 2
Add onions and garlic, sauté until softened, about 7 minutes.
- 3
Add broth, 1 teaspoon salt, and pepper.
- 4
Bring to a boil, then reduce heat to low, partially cover, and simmer for 30 minutes.
- 5
Remove from heat and blend carefully in batches, then return to pot.
- 6
Whisk egg yolks in a small bowl, slowly add 1 cup hot soup while whisking to temper.
- 7
Whisk tempered eggs into the soup, add cream and remaining 1/4 teaspoon salt.
- 8
Cook on low, stirring constantly, for 5 minutes to heat through.
- 9
Meanwhile, heat oven to 350F.
- 10
Place bread slices on a rimmed baking sheet, brush tops with melted butter.
- 11
Rub buttered side with halved garlic cloves.
- 12
Bake for 8 minutes until crisp.
- 13
Sprinkle cheese over bread and bake 3-4 minutes more until melted.
- 14
Ladle soup into bowls and top with cheese toast.
Tips
Temper egg yolks slowly by whisking in hot soup gradually; rushing this step risks scrambled eggs in your soup.
Blend soup in small batches to prevent steam buildup and splattering; let each batch cool slightly before blending.
For extra crispy toast, bake bread 1-2 minutes before adding butter and garlic to dry it out first.
Good to Know
Refrigerate soup (without toast) up to 3 days in an airtight container. Freeze soup up to 2 months; thaw overnight in the refrigerator and reheat gently on low heat, stirring occasionally. Toast is best served fresh; store in an airtight container at room temperature for up to 1 day and refresh in a 350F oven for 2-3 minutes if needed.
Prepare soup through step 7 up to 1 day ahead. Cool, cover, and refrigerate. Reheat on low, stirring often, until steaming. Bake bread and add cheese just before serving for maximum crispness.
Ladle into warm bowls and top each with 1-2 pieces of hot cheese toast. Pair with a crisp white wine like Sauvignon Blanc or a light Pinot Grigio. Serves 4-6 as a first course or 3-4 as a light main with salad.
Common Mistakes
Do not skip tempering eggs: add hot soup slowly while whisking to avoid scrambled eggs in soup.
Do not blend hot soup at high speed in a sealed blender; steam pressure can cause lid to pop off. Blend in small batches and remove center cap.
Do not cook soup after adding eggs at high heat; keep heat low and stir constantly to prevent curdling.
Substitutions
FAQ
Can I make this without eggs?
Yes. Omit eggs and increase heavy cream to 1.5 cups. The soup will be slightly less velvety but still rich. Alternatively, use 2 tablespoons of cornstarch mixed with 3 tablespoons cold water to thicken instead.
What if my soup breaks or looks grainy after adding eggs?
Strain soup through a fine-mesh sieve into a clean pot and discard solids. Reheat gently without boiling. Next time, ensure eggs are tempered more gradually and soup stays below a simmer after eggs are added.
How long can I keep the cheese toast?
Toast is best served within 30 minutes of baking. Store cooled toast in an airtight container for 1 day. Reheat in a 350F oven for 2-3 minutes to re-crisp before serving with soup.