How to make Hummus that doesn’t have a hardened layer

In Israel I have often seen hummus/falafel/thina served with a hot sauce called skhug, I have mostly seen the green variety (skhug yarok), which is a sauce made of fresh herbs, garlic, chili, lemon juice, garlic, olive oil, and some spices.

Hummus is often just served with thina on the side and with olive oil, but there is a lot of variety ... I have seen sauces based on olive oil and lemon juice, similar to what you describe (although not biter ... but the bitterness could also come from blending the olive oil). But I never saw it being prepared in front of me or it being called a particular name, but it looked a little like a thin vinaigrette.

Using my extremely limited hebrew knowledge and google I found this recipe.

The ingredients translate to:

2 hot chilies

3-4 cloves of garlic

3 tbsp olive oil

juice of half a lemon

salt

additional recomendation:

1 tsp cumin

sugar

Preparation: Put all ingredients into the food processor and turn into the sauce. Taste and adjust spices/oil/lemon juice to taste. And add sugar if too sour to balance the flavor.

You can let sit a little for the flavors to combine ... and strain out remaining bits if desired.

I am not sure if this is the sauce that you had ... but it could be very similar. Anyway ... it sounds tasty.

Maybe just not enough salt? Perhaps you forgot to add salt, or you switched from tahini with salt to without. Lack of salt, to most people, will make something otherwise well-seasoned taste bland.

Beyond that, since you're saying it also smells less garlicky, perhaps you used garlic that wasn't as strong as usual, or less of it.

The fact that it partially froze probably didn't matter, unless it was perhaps still partially frozen when you ate it. This is more in the domain of frozen desserts usually, but cold does numb the senses a bit, and the things you normally smell aren't as volatile at lower temperatures. We can make guesses about compromised texture and separation from freezing, but really, none of this is going to make something go from flavorful to completely bland.