Peach upside-down polenta cake

Grease a nine inch cake pan with butter and line the bottom with parchment so the cake unmolds easily.

Slice the unpeeled peaches thinly into wedges into a bowl.

Zest about two teaspoons of lemon into the cake sugar and toss so it doesn't clump.

Add the juice of about half the lemon and the demerara sugar to the peaches and toss gently; set aside to macerate.

Bring the milk to a simmer in the saucier over medium heat; whisk in the polenta little by little to prevent lumps and cook about a minute, until the cornmeal has absorbed the milk.

Off the heat whisk in a little vanilla extract; scrape into a bowl and cool.

After 15 to 20 minutes of macerating, strain the peach juices into the saucier and leave the fruit draining over the bowl.

Simmer the juices until thick and syrupy, reduced by a little more than half; pour into the prepared pan and spread.

Arrange the peach slices in the pan in concentric circles, rows or any pattern.

Shake the flour, baking powder and kosher salt together in a quart container.

Rub the zest into the sugar with the fingertips; beat the butter and sugar with the paddle on medium a couple of minutes until light and fluffy.

Add the room temperature eggs one at a time on medium; cold eggs would harden the butter.

On low, add the dry ingredients in three parts alternating with the cooled polenta mixture in two.

Fold by hand to scrape the bottom and sides; there is little risk of overmixing.

Dollop the batter over the fruit so the pattern holds, then smooth with an offset spatula.

Bake at 350 until golden brown, springy, and a cake taster comes out clean.

Cool in the pan about 10 minutes, run an offset spatula around the sides, set a rack on top and invert both together; leave to cool fully.