Heat the oven to 180ºC and place paper cases in a 12 hole bun tin.
In a separate bowl, mix the flour, baking powder, cinnamon and salt together.
In another mixing bowl, gradually beat the eggs and sugar until blended. Add the mashed squash, stirring well until combined.
Add dry ingredients in three batches, at a time, beating well after addition. Pour in the olive oil into the mixture gradually, mixing well. Fold in the walnuts and stir well to mix.
Spoon the mixture into the paper cases and bake for about 20-25 minutes, until firm and springy to the touch. Cool.
For topping: Whisk egg white, pinch of salt and lemon juice to soft peaks. Gradually add the sugar and continue beating until stiff.
Top 2 tablespoons of cream each muffin or pipe decorative swirls of cream of whatever shape you want. Serve, share and enjoy!