Step 1

Set up a grill for cooking over indirect heat. If using a charcoal grill, build the coals on one side only. If using a gas grill, heat one side only.

Step 2

Spray the bottom of a loaf pan with the cooking spray; line with parchment paper, then spray with cooking spray one more time. Set aside.

Step 3

Whisk together the flour, polenta, baking powder and salt. Set aside. To a stand mixer fitted with a paddle attachment, add the butter and granulated sugar. Cream until pale and fluffy, about 5 minutes. Add the eggs and egg yolk and beat again to fully incorporate. Add the ricotta, Greek yogurt, vanilla and orange zest and beat again to combine, scraping down the sides and bottom of the bowl. Add the dry ingredients and mix by hand to incorporate. Pour the batter into the prepared loaf pan, then place on the indirect-heat side of the grill, close the lid of the grill and bake until set and a toothpick inserted in the center comes out clean, 50 minutes to an hour. Remove from the grill and let cool completely.

Step 4

For the peach topping: Meanwhile, add the marmalade, orange juice and peaches to a pot, place over indirect heat and bring to a gentle simmer for the flavors to meld together, 3 to 5 minutes.

Step 5

Make the mascarpone whipped cream: Beat the heavy cream and confectioners' sugar with a blender until whipped cream forms. Fold in the mascarpone and vanilla.

Step 6

Remove the cake from the pan, then slice and serve with the peach topping and mascarpone whipped cream spooned over the top.