The appeal of panko breadcrumbs is their texture. Firm and a little crunchy when toasted, so they are your best option. However, you can also use homemade breadcrumbs, such as these ones. Just be sure not to process the breadcrumbs into a fine meal, which doesn't produce quite the right texture for this recipe. I prefer to avoid regular store-bought breadcrumbs because the texture is typically very fine, making them better for breading.