Following the chapter from de Rontzier, here is what Rumpolt has to say about snails:
There are nine dishes to be made from snails
1 Take the snails and set them to cook in water. Let them boil an hour or four. When they are boiled, draw them out of their shells and take their fore and hind parts separately. Rub the front part well with salt, that way the slime comes away, and wash them cleanly in six or seven waters so they are not slimy. Pepper them well and cut green, fragrant herbs very small. Pour good, fresh butter over them and stir it into the snails. Wash the shells nicely clean and then put the snails into them. Place them in a baking dish (Turtenpfannen) together with the shells, set them on the coals and let them boil inside their shells. If there is too little butter in it, pour on more. When they have boiled, arrange them in a bowl and serve them warm. Strew (schuet) a little pepper on the bowl, on the rim, because snails must be well peppered.
2 Take snails once they are boiled, nicely washed, and rubbed well with salt, and cut them small. Add green, fragrant herbs and place it in a fish kettle (Fischkessel) together, and add butter. Set it on coals and fry it well. Take eggs, beat them together, salt them, and let them run through a haircloth. Add pounded pepper and a little saffron and stir it into the snails with the eggs until it boils up. When it has boiled up, serve it, thus they turn out good and well-tasting.
3 Snails for frying. When they are cooked and cleaned, you salt and pepper them well and fry them (coated) with flour. When you take them out of the butter, see that they are served quickly and strew them with ginger. Thus it turns out good and well-tasting.
4 Snails cooked in liquid (eyngemacht) with pea broth, green parsley, and with butter, and well peppered.
5 Take snails that have been fried, pour mustard and butter over them and serve them warm.
6 Take snails and cook (fricusier) them nicely in butter with green, fragrant herbs that are chopped small. Pepper it well and do not oversalt it. Thuis they turn out good and well-tasting.
7 Take the hind part that you have cut off before, rub it well with salt and wash it cleanly. Throw it into hot butter and fry (roest) it thoroughly. Pepper and salt it, thus it will turn out good and well-tasting.
8 Snails cooked in pastries, especially if they are boiled and cleaned, see that they are well peppered and prepared with butter in the pastry. Thus they turn out good and well-tasting.
9 Snails served with olive oil.
These recipes again show Rumpolt as by far the better writer and quite possibly the better cook as well. Still, there seems to be general agreement that snails are seasoned exactly one way, with butter and herbs. It is hard to say whether this was long-standing custom – which is plausible – or a novel, Italianate style that made them acceptable to the wealthy and powerful. Certainly the variety in preparations shows that snails were familiar in the kitchen and served in a variety of ways.