Name: Onion Soup Mac & Cheese
Prep time: 15 min
Cook time: 35 min
Total time: 50 min
Yield: 2 servings
Cuisine: American

Delicate Kitchen Verified

March 6, 2026

Ultra creamy mac & cheese meets deeply caramelized onion soup vibes. This Onion Soup Mac & Cheese is rich, cheesy, comforting, and packed with sweet, slow-cooked onions that melt right into the sauce. Perfect as a cozy main dish or an indulgent side, and easy to double if needed.

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Onion Soup Mac & Cheese

Delicate Kitchen Verified

Ingredients

Warning0 allergens identified

Instructions

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Instructions

Cook the macaroni in well-salted water until al dente (slightly undercooked). Drain and set aside, it will finish cooking in the oven.

Heat olive oil in a large pan and add the sliced onions with a pinch of salt. Cover with a lid and cook on medium heat (level 6/9), stirring occasionally. Let them slowly caramelize for a deep, sweet flavor, this can take quite a while.

For a faster version, add small splashes of water as needed to prevent sticking, and optionally a pinch of sugar to speed up browning. Cook until soft, jammy, and deeply golden.

Set aside and divide the onions in half.

In a saucepan, melt the butter over medium heat. Add the flour and cook for about 1 minute, stirring constantly. Gradually pour in the heavy cream and milk, whisking until smooth.

Season with salt, pepper, garlic powder, paprika, and a pinch of nutmeg. Let the sauce simmer gently until slightly thickened.

Mix all three cheeses together. Add half of the cheese mixture to the sauce and stir until melted and smooth.

Add the cooked macaroni and half of the caramelized onions to the sauce and mix well.

Transfer the mac & cheese to a baking dish. Top with the remaining caramelized onions and sprinkle over the remaining cheese.

Bake at 180°C (top/bottom heat) for 30 minutes, until bubbly and lightly golden on top.

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Tips & Tricks (5)

Master the Caramelization Process 🧅
Caramelize onions low and slow (45-60 minutes) over medium-low heat with a pinch of sugar to develop deep, complex sweetness—this is the soul of the dish, so don't rush it.
Create a Silky Roux Base 🥄
Toast your flour in melted butter for 2-3 minutes before adding milk to eliminate raw flour taste and create a smoother, more luxurious cheese sauce.
Blend Your Cheeses Strategically 🧀
Use Gouda and Emmentaler for depth, reserve mozzarella for the last minute to maintain creamy texture—this three-cheese approach prevents greasiness while maximizing flavor.
Season in Layers for Balanced Flavor 🌟
Season the caramelized onions, then again when making the roux, and finally taste after adding all cheeses—layered seasoning prevents one-dimensional saltiness and enhances complexity.
Temper the Dairy to Prevent Curdling 🥛
Heat milk and cream together separately before whisking into your roux, and keep the heat moderate when adding cheese to maintain a silky, lump-free sauce.