Nedarim, Chapter Six, Mishnah One
As I previously explained, when we interpret what the one who swore intended by his vow, we interpret his words according to the normal way in which people talk. Our mishnah and those that follow explain how certain vows are to be interpreted based on this principle.
1) He who vows [not to eat] what is cooked [mebushal] is permitted what is roasted or seethed.
2) If he says, Konam if I taste any cooked dish [tabshil] he is forbidden [to eat] food loosely cooked in a pot, but is permitted [to eat] food solidly-cooked.
a) He may also eat a lightly boiled egg and gourds put in ashes.
Section one: In Mishnaic Hebrew there are three types of cooking: boiling, roasting and seething. The latter refers to cooking something in water until it is really well-done (the way they used to serve vegetables in school lunches). Since people distinguish between these types of cooking, one who swears not to eat one type, is not prohibited from the other.
Section two: If he says that he is forbidden to eat a cooked dish, tabshil in Hebrew, he may not eat food cooked loosely, such as food with a sauce. However, he may eat food cooked in a pot that comes out solid, such as cereals. Furthermore, the Talmud explains that tabshil refers to food eaten with bread, such as hummous or other spreads. Food not eaten with bread, such as hot cereal, is not called tabshil.
He may eat a lightly-boiled egg and bitter gourds mixed with ashes which sweeten them since these are also not called tabshil. (This doesnt really sound like it tastes so good, but then again, taste is culturally dependent.)