How do I get my Garlic cloves to be soft when cooked?

[Silkflowersanne]

I do a chicken thigh dish which is Chicken thighs, quickly sealed and fried, add 12 skinned chopped and de-seeded tomatoes, sprigs of rosemary and a large glass of wine with some extra water. I also add about 20 whole cloves of Garlic, a couple of bulbs normally. This simmers and reduces for about 30 minutes. The problem I have is that sometimes the Garlic is a lovely soft paste when squeezed out of its skin,how it should be but other times it is still firm. When it is a paste it is lovely and sweet but it seems that it is a 50/50 chance how it ends up. Has anyone any tips on how to ensure the Garlic ends up soft every time?

Do you bruise the garlic first? I'm thinking that if you crack the skin under the flat of a knife, you might be more successful in the centre getting hot enough to go soft...

I can't crack the skin/bulb as it would make the sauce too garlicky. As the garlick is still whole and in their skins it gives the sauce a soft gentle flavour not a typical strong flavour...........mind you when its hard its not nice to eat hence I am trying to cook it so its soft!!!
Any more ideas?

Is it always the same sort of garlic? they do vary. You could start them off first.

Leave the bulbs whole but cut the top off the garlic bulb so the clove is exposed on as many cloves as possible.

Galic absolutely varies in strength between season & country of origin & type of garlic too.