This One-Pan French Onion Pasta is the ultimate comfort meal when you want something nourishing and savory that will leave your kitchen smelling heavenly on a cold winter's night. With all the classic flavors of a French onion soup like yellow onions, gruyere cheese, beef broth, and baby bella mushrooms, you’ll be transported to a warm, cozy French chateau with just one bite. Be sure to take your time when cooking the onions for that perfect caramelized flavor!
thinly sliced
divided, can sub low-sodium vegetable broth for vegetarian
sliced
minced
reduce to 1/4 if using regular beef broth
see notes if using another type of pasta, i used this one
about half a well-shaken 13.5-ounce can
shredded, can sub mozzarella if preferred, or shredded dairy-free cheese
to garnish, optional
Preheat the oven to 425ºF. Heat the olive oil in a large, deep, lidded skillet (like this 3.5-quart saute pan) over medium heat.
Add the onions to the skillet and cook, stirring occasionally, until softened and translucent, about 12 minutes. Stir in 1/2 cup of the broth and continue cooking until absorbed by the onions, then add another 1/2 cup of broth and continue cooking until the liquid is absorbed and the onions are very soft and caramelized, another 10 to 12 minutes.
Stir in the mushrooms, garlic, thyme, salt, and black pepper and continue cooking and stirring until the mushrooms have softened, about 5 minutes.
Add the penne and stir to combine with the onion-mushroom mixture. Mix in the remaining broth (3 cups) and 3/4 cup of water, increase the heat to high, and bring to a boil. Once boiling, reduce heat to medium, cover and cook, stirring occasionally to prevent sticking, until the penne is just al dente, 11 to 14 minutes (Note: Don’t overcook the pasta since it will go in the oven after too, refer to package instructions for exact timing). See Note about pasta below.
Turn off the heat, remove the lid, and stir in the milk and about half of the gruyere (about ¾ cup) until evenly combined. Smooth out the top layer of pasta so it lays flat. Top with the remaining gruyere cheese.
Transfer to the oven and bake until the cheese is melted and bubbling, about 10 minutes. Optionally broil on high for the last 2 to 3 minutes for extra color. Cool on the counter for 10 minutes.
To serve, garnish with chopped parsley or thyme.