In a medium bowl, whisk together 4 egg yolks, 1 cup of heavy cream, and 1 cup of grated Parmesan cheese until smooth. Add a pinch of salt and a sprinkle of red pepper flakes.

In a large skillet, cook 6 strips of bacon over medium heat for 5-7 minutes until crispy. Transfer bacon to drain on a paper towel, leaving 2 tablespoons of bacon fat in the pan.

In the same skillet, add 1 chopped onion and 1 cup of sliced mushrooms and sauté for 5 minutes until onions are translucent.

Meanwhile, bring a large pot of salted water to a boil and cook 12 ounces of pasta until al dente, about 8-10 minutes. Reserve 1 cup of pasta water.

Add drained pasta to the skillet with the sautéed vegetables and toss to combine.

Remove skillet from heat and pour the creamy egg mixture over the pasta, stirring vigorously for 1-2 minutes.

Fold in the crumbled bacon and add extra Parmesan and pepper to taste before serving.