Oooooh... I haven’t had lamb liver in ages and ages.
The number 1 trick I know about ANY kind of liver, except foïe gras, is soaking it in milk for at least a few hours, and preferably all day. If you’re defrosting it? That makes it kind of perfect, since you can just place it in a bowl/jar/bag of milk and let it defrost in the milk in the fridge overnight / until you’re ready to cook it. ((If you’re like me and can’t have milk? Acidulated water can work, but it can’t be left in for more than 15 or 30 minutes or so, or the acids will start to cook it & make it weird texture-wise. It’s not as effective as milk, but it still rounds out some of the flavor, and pulls impurities.)) In either case, rinse with cool running water before cooking.
The second trick is to slice it about 1cm thick slices, and cook it like scallops... erring on the side of just underdone to finish cooking off the residual heat. So it doesn’t get rubbery or fall apart.
As far as specific recipes, I haven’t had lamb liver in so long I really don’t have any. A girlfriend of mine used to make it morroccoan style... spicing the bejeezus out of it, after soaking it and slicing it... then frying or threading onto kebabs... and serving with creamy yogurt, cucumber, & mint. But I’ve been
told the Jamie Oliver recipe for liver, bacon, & onions... on top of cabbage mashed potatoes (bubble & squeak) that a different friend of mine makes that’s WOWZA!... is actually supposed to be lamb, not the calf liver he uses. I tried looking it up online, but I don’t have Pinterest (It makes my tablet crash) & that’s the only place I can find it. (It goes wih this picture, below!
Hopefully someone else will have an “I make this all the time and it’s stellar!” Recipe for you. It’s been a reeeally long time, for me.