To prepare the tofu, toss the tofu with the cornstarch and 1 tablespoon of the Cajun seasoning until evenly coated.
Heat 2 tablespoons of the olive oil in a large sauté pan over medium heat.
Once the oil is hot, pan fry the tofu until golden brown and crispy, 8 to 10 minutes. Remove and set aside.
Heat the remaining tablespoon of oil in the same sauté pan over medium heat.
When the oil is hot, add the onion, celery, and jalapeno. Cook, stirring often, until the onion is translucent and the peppers are slightly tender, 5 to 6 minutes.
Stir in the garlic and cook for another 1 to 2 minutes.
Season with the remaining tablespoon Cajun seasoning, nutritional yeast, and chili flakes (if using). Continue to cook, stirring often, to bloom the spices, 1 to 2 minutes.
Add the uncooked pasta, diced tomatoes with their juices, parsley, broth, heavy cream, and thinly sliced bell peppers.
Stir to combine and bring to a boil.
Once at a light boil, reduce the heat to low, cover and simmer, stirring occasionally, until the pasta is al dente and the liquid has reduced into a creamy sauce, 12 to 15 minutes.
Add the parmesan and stir until it has melted throughout.
Stir in the reserved tofu and lemon juice until everything is combined. Taste and adjust seasonings, if necessary.
Serve immediately with more vegan parmesan and fresh chives. Enjoy!