• Cook the pasta shells according to the instructions on the package. Strain, save two cups of the pasta cooking water, rinse, add a teaspoon of olive oil to prevent sticking, mix and set aside.
• Preheat the oven to low heat of 100 degrees Celsius (212 F).

Pistachio Filling

• Mix vegan cream cheese, pistachio butter, nutritional yeast and salt. Taste and adjust seasoning if necessary.
• Fill a standard teaspoon with the filling and spread it on the inside of the shells.
• Arrange the shells in individual heatproof bowls or a heatproof pan, and place them in the oven uncovered.

Vegan Blue Cheese Sauce

• Melt butter and olive oil over low heat in a wok or large skillet.
• Add the grated cheese and stir on low heat until the cheese melts; gradually add the pasta water you saved earlier, and continue to cook while stirring. Avoid overcooking; cook only until the sauce reaches the desired consistency. Remove immediately from the heat. Add black pepper and salt to taste.

For Serving

• Take the pasta shells out of the oven, pour over the blue cheese sauce, and sprinkle chopped roasted pistachios and chili flakes.