Potato-Leek Soup with Mini Pierogi

unsalted butter

bunch leeks (white and light green parts only), thinly sliced and rinsed well

onion, sliced

russet potatoes (about 1 pound), peeled and sliced

garlic, minced

Kosher salt and freshly ground pepper

low-sodium chicken broth

bay leaf

heavy cream

slices thick-cut bacon, chopped