A forbidden piece not fit to be presented that becomes mixed with others of its kind, dry (יבש ביבש) — that is, it does not blend but remains whole and unrecognized — is nullified in the majority (חד בתרי בטיל), without needing 60; one may eat them one by one (מִמַּה נַּפְשָׁךְ), but not all together. But שלא במינו (a different kind) requires 60; and if they are cooked together, the liquid diffuses the taste → 60 is required (which one may add without transgressing 'nullifying a prohibition') (Shulchan Aruch, Yoreh De'ah 109 — 2 se'ifim)
חֲתִיכָה שֶׁאֵינָהּ רְאוּיָה לְהִתְכַּבֵּד שֶׁנִּתְעָרְבָה בַּאֲחֵרוֹת, מִין בְּמִינָהּ, יָבֵשׁ בְּיָבֵשׁ — חַד בִּתְרֵי בָּטֵל, וּמֻתָּר לְאָכְלָן אָדָם אֶחָד כָּל אַחַת בִּפְנֵי עַצְמָהּ, אֲבָל לֹא יֹאכַל שְׁלָשְׁתָּן יַחַד.
A piece not fit to be presented (אינה ראויה להתכבד) that became mixed with others, of its kind, dry-in-dry (יבש ביבש) — one-in-two is nullified (חד בתרי בטל), and one person may eat them each one separately, but he shall not eat all three together.
Shulchan Aruch, Yoreh De'ah 109:1LEVEL 01
Hebrew text of the 2 se'ifim with a fluent English translation. יבש ביבש and חד בתרי בטיל, the מִמַּה נַּפְשָׁךְ logic (each one separately / not all three together), מין במינו versus שלא במינו (60), and cooking the mixture explained with practical cases.
📖 StudyLEVEL 02
In-depth pilpul: why מין במינו is nullified מן התורה in the majority even לח בלח (cf. siman 98), the yesod of חד בתרי versus חד בחד, the Ran's reason to require 60 שלא במינו (גזירה שמא יבשלם), the דרבנן / דאורייתא debate (Shach and the או"ז glosses), קמח בקמח = לח בלח, חקירות and נפקא מינות.
📖 StudyLEVEL 03
Comparative tables (מין במינו / שלא במינו, dry / cooked, known before or after), golden rules, classic pitfalls (ראויה להתכבד which is never nullified, חד בתרי = majority, מבטל איסור) and memorization of the 2 se'ifim.
📖 StudyLEVEL 04
The practical halacha according to the Shach, Taz, Pri Megadim and Pitchei Teshuva, then the Sephardic poskim (Yabia Omer, Yalkut Yosef, Or LeTzion) and Ashkenazi poskim. Modern cases: a non-kosher meatball mixed with identical ones, pieces of meat one of which is טריפה, cooking such a mixture. Note: the Shulchan Aruch HaRav does not deal with this siman — this is a level of psak, not "Daat HaRav".
📖 StudyAccording to the Shulchan Aruch (YD 109:1), a forbidden piece not fit to be presented (אינה ראויה להתכבד) that becomes mixed, dry and of its kind (מין במינה יבש ביבש), with other pieces, does not blend but remains whole and unrecognized: it is nullified one-in-two by the majority (חד בתרי בטיל, אחרי רבים להטות). With מין במינו, nullification in the majority already applies מן התורה even לח בלח (cf. siman 98); so the Sages did not require 60 when dry. For practical halacha, consult your Rav.
This is the logic of se'if 1: one person may eat them each one separately, but not all three together. מִמַּה נַּפְשָׁךְ — when eating one piece, 'perhaps this is the permitted one'; and even the last, 'the forbidden one has already been eaten.' Two-and-one is still acceptable; only all three at once are forbidden (then one would surely eat the forbidden piece). The Rama adds that this is what one does לכתחילה, and that some are stringent (יש מחמירין) to discard one or give it to a non-Jew — a mere stringency. For practical halacha, consult your Rav.
Se'if 2: a dry-in-dry nullified one-in-two, if it is cooked all together, becomes forbidden again — even to eat piece by piece — if there is not 60, because the liquid (רוטב) diffuses the taste into the pieces. To cook it nonetheless, one may add (להרבות עליהם) up to 60 without transgressing 'nullifying a prohibition' (מבטל איסור), since each is already permitted. The Rama: if the mixture was known before they were cooked together, everything remains permitted (already nullified when dry, it does not become forbidden again — Rosh / Tosafot, the עיקר); and in case of loss one may rely on the lenient. For practical halacha, consult your Rav.