Toast pine nuts in a sauce pan over medium heat, stirring occasionally until golden brown. Set aside.
Add butter, olive oil and garlic to sauce pan over medium to medium-high heat until garlic is sizzling. Add half of Cajun seasoning. (Higher heat will give more flavor as the shrimp is browned slightly, but requires faster work through the following steps to keep shrimp from being overlooked)
Add shrimp and cook over until shrimp are cooked about halfway through. Turn shrimp over and add spinach to pan. Reduce heat to medium low.
Add spinach. Stir through spinach a couple of times while it wilts. While spinach is wilting, zest the rind of the lemon into the pan. Add the juice of the lemon and remaining Cajun seasoning to taste. Remove from heat.