leek and potato soup but with a proper collagen broth base

Made this yesterday and honestly it's the kind of thing my nan would've had on the Aga all Sunday. Classic leek and potato, right, but instead of just water or a stock cube I used a collagen broth as the base and it makes such a difference to the depth of it. Basically: - Two big leeks, sliced - Three medium potatoes, roughly chopped (I leave the skin on, can't be bothered) - One onion - Garlic, couple of cloves - About 800ml of the collagen broth - Little knob of butter to soften everything first Sweat it all down, add the broth, simmer til the potatoes are soft, then blend half of it. I leave half chunky because my nan always did and I can't shake it. Finish with a bit of black pepper and some chives from the garden if you've got them. It's proper autumn soup. Not fancy. But it's the sort of thing that makes you feel sorted after a long day at school, mind you.