Adjust oven rack to upper-middle position and heat oven to 475 degrees. Bring 4 quarts water to boil in large pot. Add pasta and 1 tablespoon salt and cook, stirring often, until nearly al dente. Drain pasta and return it to pot.
Finely chop pepperoni and cook in 12-inch skillet over medium-high heat until crisp, about 2 minutes. Stir in 2 cups arrabbiata sauce and bring to simmer.
Chop 1/2 cup basil.
Add pepperoni sauce, Mexican cheese blend, and most but not all of the basil to pasta and toss to combine. Transfer pasta to greased 9-inch pie plate and press with spatula to flatten surface.
Bake until golden and bubbling around edges about 15 minutes. Let cool for 10 minutes.
Reheat remaining arrabbiata sauce in microwave. Slice pie into wedges and serve with extra sauce.
To tone down the spiciness, substitute tomato sauce or your favorite jarred marinara sauce for the arrabbiata.