Bring a large pot of salted water to a boil and cook the farfalle according to package directions until al dente. Reserve 1/2 cup of pasta water before draining.

While the pasta cooks, heat the olive oil and butter in a large skillet over medium heat. Add the sliced onions, salt, and pepper.

Cook the onions, stirring occasionally, for 20 to 25 minutes until they turn golden brown and caramelized. Lower the heat if they start to brown too quickly.

In a separate dry skillet or on a baking sheet in a 350°F oven, toast the pecans for 5 to 7 minutes until fragrant. Let them cool slightly, then chop roughly.

Add the drained pasta to the skillet with the caramelized onions. Toss to combine, adding a splash of the reserved pasta water if needed to loosen the mixture.

Remove the skillet from the heat and stir in the crumbled gorgonzola until it melts into a light sauce. Top with the toasted pecans before serving.