Preheat oven to 400 degrees F. Line and grease a rimmed baking sheet. Set aside.
In a small bowl, combine the ingredients for the roasted plums, tossing to coat the chunks of plum. Spread the plums in an even layer on the baking sheet. Roast for 12 to 15 minutes, until softened.
While the plums are roasting, whip the heavy cream until it reaches stiff peaks.
In a separate bowl, combine ricotta, confectioners’ sugar, lemon zest and lemon juice. Whip (either by hand or with an electric mixer) until the mixture is smooth, approximately 30 seconds. Fold the whipped cream into the ricotta and chill until ready to serve.
In a shallow dish, beat together eggs, milk, 1 tsp vanilla extract, 1/2 tsp cinnamon and nutmeg.
Heat a large skillet over medium-high heat. Melt 1 Tbsp of butter in the pan. Dip two slices of bread into the egg mixture, coating both sides well and shaking off any excess before adding to the pan. Cook for approximately 1 to 2 minutes per side, until golden brown. Repeat the process, starting with melting 1 Tbsp butter, for the remaining slices. Serve with roasted plums and whipped ricotta.