Preheat the oven to 400 degrees.
Cook the pasta according to the directions on the package, then set aside.
Heat the oil in a large saucepan or skillet over medium heat.
Add the sausage, onion, and chopped peppers.
Cook until the sausage has begun to brown and the vegetables are tender.
Add in the garlic, and stir the mixture.
Once the sausage and vegetables are done, remove from the pan, and place on a plate.
Melt the butter in the same skillet. Once melted, whisk in the flour,
Gradually whisk in the half & half.
Increase the heat to a medium-high while whisking constantly for about 4 minutes or until it starts to become thick
Whisk in the cajun seasoning.
Remove from the heat and whisk in the cheeses until well combined.
Start adding in the pasta, sausage, crawfish, and pepper mixture. Fold in until well combined.
Transfer this dish to a large cast iron skillet and place into the oven for about 15-20 minutes or until golden and bubbly.
Serve, and enjoy!