Toss the shrimp with 1 Tablespoon olive oil and ½ Tablespoon Cajun seasoning. Set aside.
Set a large skillet over medium heat and add the Andouille sausage. Saute, stirring occasionally, until the sausage is browned, approximately 4-5 minutes. Transfer sausage to a plate and set aside.
Add 1 Tablespoon olive oil to the skillet, along with the seasoned shrimp. Spread the shrimp into a single layer without overcrowding. Cook, stirring once, just until the shrimp is opaque and starts to curl, approximately 2 minutes. Do not overcook. Transfer shrimp to the plate with the sausage.
Mix in remaining olive oil to the skillet, along with the onion, garlic, and diced bell pepper. Sprinkle with ½ Tablespoon Cajun seasoning, stir to combine. Cook, stirring frequently until the vegetables soften and develop color, approximately 4-5 minutes.
To the skillet, add the yellow squash and zucchini, saute, stirring frequently, just until browned, crisp, and tender, approximately 2-3 minutes. Remove from heat and stir in the Andouille sausage, shrimp, and fresh parsley. Stir to combine and serve immediately. Enjoy!
Stir to combine. Taste for seasoning. If needed, add a bit more Cajun seasoning, salt, and pepper. serve immediately. Enjoy!
Optional, garnish with chopped parsley. Serve and enjoy.