Season the shrimp with Cajun seasoning and salt. Heat some olive oil in a skillet over medium heat. Cook the shrimp until they are pink and cooked through, about 2-3 minutes per side. Remove the shrimp from the skillet and set aside.
In the same skillet, add 2 tbsp of butter. Sauté the shallot until translucent, about 2-3 minutes. Add the halved cherry tomatoes and the corn and cook until they start to soften and release their juices, about 5 minutes. Season with a pinch of salt.
Add the entire package of orzo pasta to the skillet and toast it for 1-2 minutes, stirring constantly.
Pour in the white wine and cook until it has mostly evaporated, stirring occasionally.
Begin adding the chicken stock, one ladle at a time, stirring constantly and allowing the liquid to absorb before adding more. Cook the orzotto until the orzo is tender and creamy, about 15-20 minutes.
Once the orzotto is cooked through, stir in the mascarpone cheese and grated Parmesan cheese until melted and creamy. Taste and adjust seasoning with salt and black pepper if needed.
Reserve 4-6 basil leaves for slicing and add the rest to the orzotto and stir to incorporate. Thinly slice the rest of the basil for topping.
Return the cooked shrimp to the skillet to warm them up.
To serve, plate with shrimp on top, garnish with freshly chopped basil chiffonade, and serve immediately.