Yes, this means delicious, but you hear this phrase more with foods like Barbecue meat dipped in sauce that you eat with your hands and is really messy. "It's finger lickin' good" because it's so delicious that you want to lick all the flavor off your messy fingers at the end 😁👍🏽

Yes, you are correct, it means that the food is VERY good, SO good that you would lick your fingers to get every bit of it. This is one of the slogans, marketing ways used by Kentucky Fried Chicken KFC, where I originnaly come from, the state of Kentucky in the USA! The ads, the marketing for KFC uses this phrase "Kentucky Fried Chicken, its finger licking good!" to express this same idea---that our food is SO good that you will lick your fingers.

"That cake is finger licking good" is the proper way. Another example is "that cake is the bomb". This expression implies that you really enjoy something.

Right I got it. thanks

"that cake is finger licking good" is the right way of saying that. There's no need to use the pronoun IT in the middle of the sentence because it already has a subject which is "that cake"