Heat 6 tablespoons of the olive oil over medium-low in a 12-inch skillet or small Dutch oven. Add the pumpkin seeds and, when the oil starts sizzling, stir occasionally until golden brown, about 3 minutes; turn off heat. Stir in the turmeric and season lightly with salt and pepper. Transfer to a small serving bowl.
Heat the remaining 2 tablespoons of olive oil over medium-high in the same skillet. When warm, add the diced leeks and a pinch of salt. Cook, stirring until just softened, about 3 minutes. Stir in the garlic, the beans and stock. Bring to a simmer then turn heat down to low.
Sprinkle in the cheese, stirring vigorously to combine. When the cheese has melted into the broth and the mixture looks creamy, season to taste with salt and then turn off the heat. While the beans are still hot, roughly chop the basil leaves and stir into the beans.
Serve hot, in bowls or on plates, drizzled with the sizzled pumpkin seeds, a squeeze of lemon juice and more black pepper and grated Parmesan, if desired.
mark.goadrich