In large, nonstick skillet over medium heat, heat oil. Add shallot and cook until softened, 2 minutes. Stir in cauliflower rice, 1/4 teaspoon salt and pepper; cook 2 minutes.
Sprinkle flour over cauliflower and stir to incorporate then add milk and cook, stirring occasionally, until it comes to gentle boil. Stir in 1/2 cup Parmesan cheese until incorporated then add shrimp and peas.
Return to simmer. Continue cooking, stirring occasionally, until shrimp are pink and no longer translucent and sauce has thickened, about 5 minutes. Season with additional salt, to taste, then garnish with basil and remaining Parmesan cheese.