Butternut Squash with fennel

2 pounds butternut squash peeled, halved and seeded 2 1/2 tablespoons olive oil or other vegetable oil 1 large red onion minced 2 cloves garlic or to your own[...]

2 tablespoons unsalted butter 1 1/2 cups sliced leeks , white parts only 1 tablespoon minced garlic 6 cups butternut squash, peeled and roughly diced 3 cups[...]