Italian Penicillin Soup Recipe
A scientifically optimized recipe for Italian Penicillin Soup (Pastina), utilizing starch emulsification and aromatic extraction to create the ultimate comforting, nutrient-dense broth.
- Starch gelatinization from cooking pastina directly in broth creates a velvety, naturally thickened body.
- Finely pureed mirepoix maximizes surface area contact, releasing concentrated volatile flavor compounds.
- An egg yolk and Parmigiano-Reggiano liaison creates a stable, rich emulsion without heavy cream.
The secret to a superior Italian Penicillin Soup lies not in long-simmered mystery, but in the precise control of starch gelatinization and emulsion stability. While many home cooks boil pastina in separate water, cooking these tiny pasta stars directly in the broth releases amylose molecules that naturally thicken the liquid.
This technique transforms thin broth into a velvety elixir.
At temperatures above 140°F (60°C), the starch granules in the pasta absorb water, swell, and burst, releasing starch into the surrounding liquid. This process, known as starch gelatinization, creates a suspended network that traps water molecules and increases viscosity. To further enhance this structure, we introduce a classic emulsion of egg and cheese, similar to the technique used in Avgolemono Soup, which adds fat and protein to the matrix without breaking.
Finely pureeing the mirepoix before simmering maximizes the extraction of soluble sugars and sulfur compounds. This step ensures a smooth texture and intense aromatic depth.
This soup serves as a comforting, easily digestible option, much like a traditional Chicken Noodle Soup, but with a much silkier texture. By incorporating a high-quality chicken bone broth, you introduce gelatin, which coats the throat and provides a rich, satisfying mouthfeel.
Italian Penicillin Soup
Ingredients
- 4 cups high-quality chicken bone broth
- 1/2 cup pastina (star-shaped pasta, preferably Barilla or De Cecco)
- 1 medium carrot, peeled and roughly chopped
- 1 celery stalk, roughly chopped
- 1/2 small yellow onion, roughly chopped
- 1 large egg
- 1/2 cup finely grated Parmigiano-Reggiano cheese
- 1 tablespoon unsalted butter
- Kosher salt (Diamond Crystal) and freshly cracked black pepper to taste
Directions
- In a food processor, combine the carrot, celery, and onion. Pulse until finely minced or pureed into a paste to maximize surface area for rapid flavor extraction.
- In a medium saucepan, melt the butter over medium heat. Add the pureed vegetables and cook for 3 to 4 minutes until fragrant and translucent, ensuring they do not brown.
- Pour in the chicken bone broth and bring to a boil. Reduce the heat to a gentle simmer, stir in the pastina, and cook for 8 to 10 minutes, stirring frequently to prevent the pasta from sticking to the bottom of the pan as the starches gelatinize.
- While the pasta cooks, whisk the egg and Parmigiano-Reggiano together in a small bowl until a smooth, thick paste forms.
- Remove the saucepan from the heat. Slowly ladle 1/4 cup of the hot broth into the egg and cheese mixture while whisking constantly to temper the egg, then pour the tempered mixture back into the soup, stirring vigorously to create a creamy, stable emulsion. Season with salt and black pepper to taste.
Notes
Always temper the egg mixture before adding it to the hot soup to prevent curdling.
- Use Diamond Crystal Kosher Salt; if substituting with Morton Kosher Salt, reduce the volume by half (use 1/2 teaspoon for every teaspoon of Diamond Crystal) to avoid over-salting due to differences in crystal density.
- The addition of Parmigiano-Reggiano introduces free glutamates (natural MSG) and dairy fats that bind with the egg proteins, preventing the egg from coagulating into hard clumps when exposed to heat.
- Do not let the soup boil after adding the egg and cheese mixture. If you boil the soup after emulsification, the proteins will denature and clump, causing the smooth sauce to split into watery broth and scrambled eggs.
- Pastina continues to absorb liquid as it sits. After 24 hours in the refrigerator, the pasta will swell significantly, absorbing almost all the broth and turning the soup into a thick porridge.
- If you do not have a food processor to puree the vegetables, use a microplane or box grater to grate the carrot, celery, and onion directly into the pot, which achieves a similar surface area for rapid flavor release.
Serving Suggestions
Serve this soup immediately while the emulsion is at its peak stability and the pasta is perfectly al dente. Pair it with contrasting textures and bright acids to balance the rich, savory broth.
- A slice of toasted Artichoke Bread provides a crunchy, savory contrast to the velvety soup.
- A squeeze of fresh lemon juice adds bright acidity to cut through the rich, fatty egg yolk and cheese emulsion.
- A drizzle of high-quality extra virgin olive oil pools on the surface, offering a grassy aroma with every spoonful.
- A side of crispy prosciutto chips introduces a salty, shattered texture that contrasts beautifully with the soft pastina.
Storage and Reheating
Store any leftover soup in an airtight glass container. Keep it in the coldest zone of your refrigerator for up to 3 days.
Freezing is highly discouraged for this recipe. The starch network in the pastina will undergo retrogradation upon freezing and thawing, resulting in a mushy, water-logged pasta texture and a completely broken emulsion.
To reheat, place the leftovers in a small saucepan over low heat. Because the pasta will have absorbed the liquid, stir in 1/4 to 1/2 cup of fresh chicken broth or water to restore the soup's original consistency. Heat gently while stirring constantly to prevent the pasta from scorching on the bottom of the pan.
Alternatively, microwave in 30-second intervals at medium power. Stir between each interval to distribute the heat evenly and prevent the egg emulsion from splitting.
Prepare the broth base ahead to save time.
Ingredient Substitutes
You can adapt this comforting soup with these precise ingredient swaps to suit your pantry availability.
- Pastina: Substitute with acini di pepe or orzo at a 1:1 ratio, but increase the pasta cooking time by 2 to 3 minutes as these larger shapes take longer to hydrate.
- Parmigiano-Reggiano: Substitute with Pecorino Romano at a 1:1 ratio, but reduce the added kosher salt slightly to account for the Pecorino's higher sodium content.
- Chicken Bone Broth: Substitute with a rich vegetable broth at a 1:1 ratio, though you will lose the gelatinous mouthfeel provided by animal-based collagen.
- Egg: Substitute with 2 tablespoons of heavy cream at a 1:1 ratio for richness, though this will alter the traditional flavor profile and reduce the protein content.
This Italian Penicillin Soup is a masterclass in utilizing simple kitchen staples to achieve culinary comfort through scientific precision. By mastering the starch-and-egg emulsion, you can create a deeply restorative bowl in under thirty minutes. Keep a box of pastina in your pantry so you are always prepared to whip up this comforting classic.