Hello akwedeen, welcome to the forums. A hint or tip for future posts, you'll get more responses and better feedback if you use the spoiler feature for how the hand ended up playing out OR if you withhold how the hand played out for a day or so.
OTTH: What a dream scenario to be in!! Less than 100 BBs deep, flopping a set on an Ace high board in position facing a donk bet and a min raise. These are the spots we live for. I think flatting the $20 or 3-betting are both decent options in this spot. With a BB donk into the preflop raiser(PFR) and the PFR min-raising, you should be able to get your less than 100BB stack in by the river in any scenario.
What's your table image to the rest of the players? Would a raise in this situation send off any red flags to your opponents that shuts them down from betting on future streets? The answer to that question probably indicates the best way for you to play the hand moving forward.
A $10 donk lead by the BB indicates that player probably has an Ace with a weaker kicker ( AT, A9, A8, A7). With MP min-raising BB donk bet on the AK3 board, he's telling you he has an Ace and at minimum he has a solid kicker (AA,AK, AQ, maybe AJ, and let's add A3cc in there as well for a flopped two pair). The only non-Ace hand he has in this range is KK. Knowing that information, it makes it really hard for MP/PFR to have AA as he would have to have the only 2 Aces left in the deck.
I think the best play is to call the flop raise by the PFR and then ship it all in against MP/PFR Turn bet. This will immediately allow an extra $10 in the bot by the BB calling the min bet. It also allows the BB to potentially catch 2 pair and potentially double you up as well.
$25 in the pot Pre after $8 raise by MP.
Flop ($25)
BB($390): Bets $10
MP($190): Raises to $20
Hero(180): Flats $20
BB($380): calls the min-raise
Turn($85)
BB ($370): Checks (unless he/she hits two pair, then probably leads out)
MP($170): Will most likely continue betting somewhere around $50-$65 leaving behind around ($110 - $120), virtually committing himself to the pot (in these stakes, you'll rarely see a fold).
Hero($160): All in
BB: folds, unless he hits two pair then he is all in as well.
MP: Calls of remaining stack
There are a lot of hands that MP will bet/call off on turn especially if he has any equity or can improve to the nuts. (AQ in this spot with the board reading AK3T, where even if he is behind he can still occasionally hit the straight. The only scare card you don't really want to see on the turn is a King, as that will probably shut down most of the Ace's from betting (and in this case, cause you to lose the hand overall
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