Preheat oven to 350 °F and grease a 9-x-13-inch pan.
Beat butter and sugar until light and fluffy. Beat in sour cream, then add eggs, one at a time, beating well after each addition.
Stir in vanilla and almond extracts.
In a separate bowl, stir flour, ground almonds, lemon zest, baking powder, nutmeg and salt to combine.
Add to butter mixture and stir just until incorporated.
Spread batter into prepared pan and arrange fruit over batter, pressing in gently (if using plums or apricots halves, arrange with flat-side up).
Sprinkle lightly with sugar and cinnamon and bake for 25 to 30 minutes, until a tester inserted in the centre of the cake comes out clean.
Cool completely before slicing into squares and serving.