Preheat the oven and prepare the cake base.

In a bowl, combine flour and baking powder.

In a separate bowl, cream together sugar and softened butter, then add eggs and vanilla extract, mixing well.

Gradually add the flour mixture to the wet ingredients, alternating with milk until combined.

Pour the batter into a prepared cake pan and bake for 25 minutes.

Allow the cake to cool completely.

In another bowl, whip the heavy cream and powdered sugar until stiff peaks form.

Fold in the diced kiwis, gelatin mixture, and lemon juice to the whipped cream.

Layer the kiwi mousse over the cooled cake base and refrigerate until set.