Center a rack in the oven and preheat the oven to 350°F Put a 8x2 inch round cake pan on a baking sheet.
Whisk together the flour, baking powder, salt and cinnamon.
Melt 6 tablespoons butter in a small saucepan. Sprinkle in 6 tablespoons sugar and cook, stirring, until the mixture comes to a boil. Pour this evenly over the bottom of the cake pan, then scatter over the nuts and top with the cranberries, smoothing the layer and pressing it down gently with your fingertips. Set aside.
Working with a stand mixer, preferably fitted with a paddle attachment, or with a hand mixer in a large bowl, beat the remaining stick of butter on medium speed until smooth. Add the remaining 1/2 cup of sugar and continue to beat until pale and creamy, about 3 minutes. Add the eggs one at a time, beating for 1 minute after each addition and scraping down the bowl as needed. Pour in the vanilla. Reduce the mixer speed to low and add half of the dry ingredients, mixing only until they disappear into the batter. Mix in the milk, then the rest of the dry ingredients. Spoon the batter over the cranberries and smooth the top with a rubber spatula.
Bake for 40-45 minutes, or until the cake is golden and a thin knife inserted into the center of the cake comes out clean. Remove it from the oven and 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 berries stick to the pan-as they might-just scrape them off with a table knife and return them to the cake.
If you want the glaze, warm the jelly in a small saucepan over low heat, or in a microwave. Gently brush the glaze over the hot cake. Let the cake cool at least 20 minutes before serving.