Heat the oven to 375 degrees.

Place 2 tablespoons butter, onion and 2 rosemary branches into a skillet and cook for 5 minutes over medium heat. Remove from the heat and let cool for 10 minutes. Remove the rosemary.

While the onions are cooking, combine the pumpkin, mascarpone, nutmeg, salt and eggs in a large bowl. Stir well to mix. Once the onion mixture has cooled, add the onions to the pumpkin mixture. Stir well to combine.

In a medium sized bowl combine the egg yolks, cream and gruyere. Mix well. Set aside.

Place the skillet back onto the cooktop (it’s okay if a few onions remain in the pan) and add 1 tablespoon of butter, pancetta and 3 rosemary sprigs. Over medium to medium-high heat let the pancetta crisp, about 8 minutes.

Add the panko to the skillet and let them absorb the butter and pancetta fat, about 30 seconds. Remove the panko pancetta mixture from the heat and add to the egg yolks mixture. Stir to combine.

Place the skillet back onto the heat and deglaze the pan with the wine. Bring to a simmer and let reduce by half. Pour the wine mixture into the pumpkin puree and stir well to combine.

Pour the pumpkin mixture into a medium-sized baking dish. Top with the panko pancetta mixture. Bake in the oven for 35-40 minutes or until the top is browned and bubbly and the pumpkin is set. Serve warm.