Butternut Squash with Rosemary Breadcrumbs

This is another recipe from Parker Farms (thanks F&J!). I've modified the original recipe to be gluten and casein free - it remains one of my favorite butternut squash recipes. You can use any GFCF bread for the fresh bread cubes...I used two leftover Garlic Herb Sandwich Rolls with great results.1/4 cup canola oil or olive oil3 cups thinly sliced leeks, white and pale green parts only2 pounds