2) In a medium saucepan, combine the milk, single cream, 115g sugar and the butter. Bring the mixture to a boil over a medium-high heat.
3) Very slowly, to avoid lumps, whisk in the grits and salt. Add the egg yolks to a small bowl and the egg whites to a large bowl. Stir a little of the hot grits into the egg yolks, to temper, then add the yolks to the pan and whisk to combine.
4) Add the lemon zest, cinnamon and nutmeg. Reduce the heat and simmer, stirring constantly, until the mixture is thickened and cooked through, about 15 minutes.
5) Using an electric mixer, whip the egg whites to soft peaks. Add the remaining 2 tablespoons of sugar, and continue whipping until stiff peaks form. Fold 1/3 of the meringue into the grits to lighten, and then fold in the remaining meringue.
6) Scrape the batter into the prepared souffle dish and bake on the centre oven shelf until the souffle is golden but the centre still jiggles, 40 to 45 minutes. Serve immediately.