Question
We have a single oven in our home, which we cook basari in. The oven is clean - there are no "meat splatters" all over the insides. I cook bread in this oven (I found a source for grain grown in E"Y, and the bread is just supreme).
Question 1: Can I toast the bread cooked in the oven in our "halevi toaster"? And, if so, can I put butter on the toast?
Question 2: If I toast the bread in the basari oven, can I put butter on the toast?
Thank you and Shabbat Shalom!
Response
1. Some Pos'qim hold that according to the Talmud Bavli (P'sahim 76b) all agree that l'khathhila one may not roast a piece of kosher meat together with a piece of non-kosher meat in the same oven. B'dhi'avadh, i.e. where this has been already done, Rav forbids eating the kosher meat and Lewi permits it.
2. Other Pos'qim, such as the Ran (to Riph Hulin 32a), prove from the above-mentioned discussion of the TB that Lewi permits the roasting of the kosher meat in the same oven as the non-kosher even l'khathhila. This is borne out by the Talmudh Y'rushalmi (T'rumoth 10:2) which says so explicitly.
3. The G'onim and most of the Rishonim were poseq like Lewi b'dhi'avadh, including Halakhoth G'dholoth, Riph, Rashi, Rambam, Rashba and Ran. L'khathhila, according to these Pos'qim, we do not do so.
4. The TB in P'sahim also discusses the status of bread baked in the same oven together with meat. Some Pos'qim hold that it may be eaten with milk, others forbid this.
5. The above applies to the two items being in the oven simultaneously. If the non-kosher meat was roasted first and removed, and only then was the kosher meat placed in the same oven and roasted, there is no basis to claim that it is asur even according to Rav. The claim that some remnant of the former may be still present in the oven is far-fetched and incorrect for a number of reasons: a) if it's not the same day, it cannot impart a desirable flavour (nothen ta'am liphgham), and b) even if meat was roasted in the oven that very day, the matter that may still exist on the walls of the oven is minute in amount and irrelevant. Not one of the Rishonim claims that this is an issue. The same applies to bread and meat.
6. You may therefore bake bread in your 'b'sari' oven and later eat it with butter. You may also toast it in your 'halavi' toaster. It is advisable, but not essential, to put foil or a baking pan under the bread when baking.
Rabbi David Bar-Hayim