Preheat oven to 180°C / 350°F (no fan). Grease and flour a 28cm / 11-inch tart tin with removable base.
Drain the cherries over a small saucepan and set both aside.
In a large bowl, beat the soft butter and sugar with an electric mixer until pale and well combined.
Add eggs, one at a time, beating well after each.
Sift in the self-raising flour and nutmeg.
Pour milk and vanilla into the bowl. Gently fold the mixture using a spatula. A few lumps are fine.
In a clean bowl, whisk egg whites until soft peaks form. Do not overbeat.
Gently fold in about 1 big, heaped cup of drained cherries and optional flaked almonds.
Gently fold in the whipped egg whites. Don’t overmix.
Spoon the batter into the prepared tin and smooth the top.
Scatter a few extra cherries on top. Reserve the rest for syrup.
Bake for 25–35 minutes, or until lightly golden and the cake springs back when touched.
While the cake bakes, simmer the reserved cherry liquid over low heat until reduced and syrupy. Add reserved cherries and set aside.
Let the cake cool for 10 minutes before removing from tin. Dust with icing sugar.
Slice and serve with sweetened whipped cream and a drizzle of cherry syrup.