Preheat the oven to 350 degrees F.

In a bowl, whisk together the flour, baking powder, cinnamon, nutmeg and salt. Set it aside.

Melt 6 tablespoons of the butter and 6 tablespoons of the sugar on medium heat in a small saucepan. Continue to stir until the mixture comes to a boil.

Pour this evenly over the bottom of the cake pan and top with the rhubarb, smoothing the layer and pressing it down gently with your fingertips.

Using an electric mixer beat the remaining butter (1/2 cup) on medium speed until smooth. Add the remaining sugar and continue to beat until the mixture is pale and creamy. Pour in the vanilla or almond extract and then add the eggs one at a time, beating well after each addition and scraping down the bowl as needed. Reduce the mixer speed to low and add half of the dry ingredients, mixing only until they disappear into the batter. Pour in the milk, mix, then add the remaining flour. The cake batter will be thick.

Spoon the batter over the rhubarb and smooth the top with a rubber spatula.

Bake in a preheated oven for 45-55 minutes, or until the cake is golden and a tester inserted into the center of the cake comes out clean. Transfer to a cooling rack and let the cake cool down for about 15 minutes before you remove them from the pan. Run a blunt knife between the sides of the pan and the cake. Carefully turn the cake out onto a serving platter. If any of the rhubarb stick to the pan – as they might – just scrape them off with a knife and return them to the cake.

Quickly heat up the jam either with a microwave or on stovetop until it has consistency of a glaze. Brush the top of the rhubarb pieces with the heated jam for a shinier topping.