Preheat oven to 350°F (177°C).

In a medium bowl, whisk flour, baking powder and salt. Set aside.

In a separate bowl, beat zest, 1/2 cup butter, 1 cup sugar and 1 tsp. vanilla on medium high speed with electric mixer until pale and fluffy, about 4 minutes. Set aside.

Add 1/2 cup of butter to a 9 inch round cake pan, and place in oven to melt.

Add 1 teaspoon vanilla and 1/2 cup of sugar to melted butter in cake pan and whisk to combine. Place pan back in the oven and when butter has started to bubble and just barely brown, add 2 tbsp. orange juice and whisk to combine. Add cranberries and place back in the oven for 5 minutes.

While pan is in the oven, add eggs to butter mixture, one at a time, with the mixer on low speed.

Beat until fully incorporated, then add flour mixture in 2 batches alternating with the milk and remaining orange juice.

Remove pan from oven.

Gently scoop batter on top of cranberries and smooth top with an offset spatula.

Bake until cake is golden and puffed and a cake tester (knife) comes out clean, 45 to 50 minutes.

Transfer to a wire rack to cool in the pan for 10 minutes.

Run a knife (or offset spatula) around the edge of the pan to loosen cake, then invert onto wire rack to cool completely.