Preheat oven to 375°.
Mix together 2 teaspoons olive oil, ¼ teaspoon salt and ¼ teaspoon black pepper. Brush onto the inside of the squash.
Line a baking sheet with parchment paper and place the squash on it, flesh-side down. Bake for 30 minutes, until golden and tender.
In a large skillet over medium high heat, cook the sausages and the leeks in 1 teaspoon of olive oil, until the sausages are browned and slightly crisp and the leeks begin to caramelize, between 7 and 10 minutes. R
Add the garlic, kale and broth. Cook for another 3 to 4 minutes, until the kale begins to wilt. Remove from heat.
In a large bowl, mix together the sausage, leek and kale mixture, breadcrumbs, nutritional yeast and the remaining sea salt and pepper.
Stuff the squash with the mixture. Sprinkle a little more breadcrumbs and nutritional yeast on the top, if you like. Bake for 10 to 15 minutes, until heated throughout.