Step 1: Caramelize the Onions

In a large Dutch oven (7 qt recommended), heat 3 tablespoons olive oil and 2 tablespoons butter over medium heat.

Add the sliced onions along with 1/8 tsp each of salt and pepper.

Cook, stirring occasionally, for 30–35 minutes, or until the onions are deeply caramelized and golden brown.

Reduce heat if onions start to scorch. Add a bit more oil or butter as needed.

Stir more frequently near the end to avoid burning.

Build the Flavor Base

Once onions are caramelized, add garlic, red pepper flakes, Worcestershire sauce, and soy sauce. Cook for 30 seconds, until fragrant.

Add Liquids & Seasoning

Add 5 1/2 cups water and half of the evaporated milk to the pot.

In a separate bowl, whisk the cornstarch into the remaining evaporated milk, then stir into the pot.

Increase heat to high. Stir in beef bouillon, parsley, thyme, oregano, paprika, and pepper. Bring to a boil.

Cook the Pasta

Once boiling, add the uncooked pasta. Stir to evenly submerge in liquid.

Reduce heat to a gentle boil/simmer over medium-high and cook uncovered for 20–25 minutes, or until pasta is al dente.

Stir frequently to prevent sticking and burning.

The pasta should still have some excess liquid left at the end—this becomes the sauce.

If the liquid evaporates too fast, add more water ½ cup at a time as needed.

Add Cheese & Finish

Turn off the heat. Gradually add Gruyere cheese, a handful at a time, stirring until melted.

Add Parmesan cheese and stir until fully incorporated.

Taste and season with additional salt or pepper if needed.

For extra creaminess, stir in a splash of milk or water if desired.

Garnish with fresh parsley and serve immediately.