For the Cranberries

1. Generously grease the bottom and sides of a 9″ springform pan with unsalted butter. Lay a circle of parchment on the bottom of the pan (do not go up the sides). Place the springform pan on a large, rimmed baking sheet and set aside.
2. Rinse the cranberries in their mesh bag under cold running water. Fill a large bowl about halfway with cold water and set aside.
3. Slice the cranberries in half crosswise and place in the bowl of water (the seeds will sink to the bottom and the berry halves will float) and discard any mushy cranberries. Once all berries are in the water, agitate slightly to release the seeds, then transfer the berries with a slotted spoon to a colander or salad spinner.
4. Empty the bowl with the seeds, rinse and dry. Add the drained/spun berries back to the bowl, then add the walnuts and Lakanto sweetener, stir to incorporate, and set aside.

For the Cake

1. Preheat oven to 350 degrees F with oven rack at center position. Melt the butter and set aside to cool.
2. In a large bowl, combine the beaten eggs, Lakanto sweetener, vanilla, salt, and cooled butter, Add the flour and baking powder to a sifter and sift into the wet mixture, then fold together with a silicone spatula, scraping the bottom and sides of the bowl, until fully combined and lump free. The mixture will be a thick batter.

Putting it Together

1. Give the cranberry mixture another stir, then add to the prepared springform pan and push down firmly to form a flat, even layer.
2. Transfer the batter to the pan in large distributed spoonfuls and smooth evenly with the silicone spatula.
3. Bake for 35 minutes. Remove from oven, use a small, sharp knife to go around the edge of the pan, and let sit for 15 minutes on a cooling rack.
4. Run a knife around the edge again, then open and remove the springform. Place an inverted plate on top of the cake and hold in place with the palm of one hand. Carefully slide the other hand under the baking sheet (it should be cool enough now but wear an oven mitt just to be safe), and quickly flip everything over. Remove the baking sheet and set aside.
5. Carefully remove the bottom of the springform pan from the cake. If it is sticking, poke inward with a small sharp knife to begin releasing the cranberry layer. The parchment is a huge help. If any of the cranberries remain stuck to the pan, simply transfer them to the cake to fill in any voids. Garnish with more walnuts, peeled orange zest, and orange wedges, if desired. Serve warm, at room temperature, or chilled.