סימן עב סעיף יט
הָא דְּמֻתָּר לְהַטְמִין גַּם כְּשֶׁאֵין הַתַּנּוּר טוּחַ בְּטִיט, זֶהוּ דַּוְקָא כְּשֶׁמַּטְמִינִין בָּשָׂר, וְכֵן אֲפִלּוּ כְּשֶׁמַּטְמִינִין מִינֵי קִטְנִיּוֹת וּמִינֵי בָּצֵק, אֶלָּא שֶׁמַּטְמִינִים זְמַן הַרְבֵּה קֹדֶם הַלַּיְלָה בְּאֹפֶן שֶׁיּוּכְלוּ לְהִתְבַּשֵּׁל קֹדֶם הַלַּיְלָה קְצָת עַד שֶׁיִהְיוּרְאוּיִים לַאֲכִילָה עַל יְדֵי הַדְּחָק. אֲבָל כְּשֶׁמַּטְמִינִין מִינֵי קִטְנִיּוֹת וּמִינֵי בָּצֵק סָמוּךְ לַלַּיְלָה, צְרִיכִין דַּוְקָא לָטוּחַ אֶת הַתַּנּוּר בְּטִיט (כִּי מִן הַסְּתָם אֵינוֹ גָּרוּף וְקָטוּם כָּרָאוּי). וּצְרִיכִין לִזָּהֵר בָּזֶה. כִּי אִם לֹא עָשׂוּ כֵן, אָז אֲפִלּוּ בְּדִיעֲבַד הַמַּאֲכָלִים אֲסוּרִים עַד לְמוֹצָאֵי שַׁבָּת בִּכְדֵי שֶׁיֵּעָשׂוּ.
The law which permits us to place cooked food in the oven even when the oven door is not sealed with mortar applies only to meat, and also to various kinds of legumes [peas, etc.], and also to various types of dough, provided you put them in the oven a long time before nightfall, so that the food will be cooked a little before nightfall, until it reaches the stage when it can be eaten with difficulty.94That is one half or one third cooked. This is called ma’achal ben Derusai, the food of a gang of bandits who always ate on the run. But if you place legumes or types of dough in the oven close to nightfall you must seal the oven door with mortar.95The difference being since meat takes a long time to cook, it will be left untouched till tomorrow, and there is no need to stir the coals, whereas legumes and doughs take less time to cook, and we fear that he will stir the coals to make it edible for Friday night [Poskim, Magein Avraham etc.]. (For probably the coals were not removed or were not covered and cooled with ashes properly.) You must be careful about this; for if you failed to do this, the food is forbidden even bediavad (post factum) until after Shabbos,96[Shulchan Aruch Harav] You and your family may not eat it even when it was done without intent, but others may eat it even on Shabbos if it was done without intent. until enough time has elapsed to accomplish what was done (on Shabbos)
תנא דבי אליהו כל השונה הלכות בכל יום מובטח לו שהוא בן העולם הבא שנאמר הליכות עולם לו אל תקרי הליכות אלא הלכות (נדה ע"ג.)