Pour vegetable or chicken broth into a medium saucepan and bring to a simmer. Lower heat and keep broth warm.
In a large saucepan, cook pancetta over medium heat until browned and crispy, about 5-7 minutes. Remove to a paper-towel lined plate with a slotted spoon and set aside.
If you want to fry sage for garnish, add 8 sage leaves to the same pan with pancetta oil and let fry for about 20 seconds, until crispy. Immediately remove with a slotted spoon and transfer to paper towel-lined plate.
If saucepan looks dry, add 1 tablespoon butter and let melt. Add onion and cook over medium heat for about 5 minutes until starting to soften. Add garlic and cook for another minute, until fragrant.
Add arborio rice to the saucepan and cook for about 2 minutes, stirring a bit, until it’s translucent around the edges.
Pour wine into saucepan and cook, stirring until it's absorbed, about 2 minutes.
Add 1 cup of the warmed broth to the rice. Stir and let the rice absorb the stock. Once the broth is absorbed, continue to add more, a cup at a time, stirring and letting it absorb before adding more. You don't have to stir non-stop, but stir occasionally to make sure rice doesn't start sticking to the bottom of your saucepan. Continue with the rest of the broth, or until the rice is nice and tender, but still firm.
Stir in pumpkin puree, nutmeg, salt, and pepper. Cook for 2-3 more minutes, until warmed through.
Remove from heat and stir in parmesan cheese, mascarpone, remaining tablespoon butter, cooked pancetta, and 2 teaspoon chopped sage.
Serve pumpkin risotto topped with toasted pumpkin seeds and fried sage leaves if using.