Set a skillet over medium-high heat. Add the olive oil and the pancetta and cook, stirring constantly, for 3 minutes. Add the shallot and garlic and cook for 2 minutes more.
Transfer the pancetta mixture to the bowl of a slow cooker. Add the chicken broth, squash, rice, and white wine. Set the slow cooker to high and the timer to 1 hr 30 min. Give the risotto a good stir every 30 minutes (this will allow the rice to cook evenly).
About 15 minutes before the risotto is done, preheat the oven to 200°C (400°F). Cover a baking sheet with parchment paper. Place the portobello mushrooms top side down on the baking sheet. Set aside.
Once the timer is done, stir in 175 mL (3/4 cup) of the shredded Saputo Pecorino Romano cheese and heavy cream and stir until the cheese is melted and the risotto is creamy. Turn off the slow cooker.
Season the portobello mushrooms with salt and pepper. Fill each mushroom with about 250 mL (1 cup) risotto. Sprinkle with the remaining shredded Saputo Pecorino Romano Cheese. Bake for 15 minutes, or until the mushrooms are tender. Broil until the cheese is golden brown.