Combine the Panko breadcrumbs, Parmesan cheese, parsley, and optional red pepper flakes in a shallow bowl. Stir until the Parmesan and herbs are evenly dispersed through the crumbs.

Boil the tortellini until it is 1 minute short of al dente, then drain it thoroughly and coat each piece generously with flour. The pasta should be tender but still firm enough to finish cooking without becoming mushy.

Dip the floured tortellini in the beaten eggs, then roll it through the Parmesan panko mixture and press gently to secure the coating. The crumbs should cling in an even layer with no wet patches showing through.

Heat canola oil in a Dutch oven to 375°F, using enough oil to cover the tortellini by 1 to 2 inches. The oil should shimmer steadily without smoking.

Fry one breaded tortellini first to check the heat, then cook the remaining pieces in batches for about 5 minutes per side. The test piece should sizzle promptly but calmly, and finished bites should be deep golden brown.

Transfer the fried tortellini to paper towels and gently blot away surface oil before serving with warm marinara sauce. The crust should stay crisp while the cheese-filled pasta remains hot and tender inside.