1. Cook fettuccine according to package directions.

2. While fettuccine is cooking, sauté the onion and garlic in oil in a nonstick frying pan, until tender. 

3. In a small bowl, whisk together the flour and evaporated milk until smooth.

4. Add the flour mixture to the frying pan, stirring well. Stir in the salt, white pepper and cayenne pepper.

5. Bring to a boil; cook and stir for 2 minutes or until thickened.

6. Reduce heat. Stir in shrimp and basil.

7. Simmer, uncovered, for 4 minutes or until shrimp turn pink.

8. Drain the fettuccine and place in a large bowl. Add the shrimp mixture and toss to coat.