Preheat oven to 350℉. Grease baking dish (8" or 9" cheesecake pan if you know it doesn't leak at all, or regular round cake pan). (I use coconut oil or Grain Brain's palm oil to grease.) Place cranberries in the bottom of cake pan, spread out evenly. Set aside. Make easy fast caramel in small saucepan: Place coconut cream and coconut sugar in small saucepan. Turn heat to medium and bring to simmer, stirring/whisking to dissolve sugar.
Once simmering, reduce heat to very low and maintain simmer for 5 minutes. Stir occasionally. Turn off heat and stir in sea salt. Set aside but keep warm.
In a medium size mixing bowl, combine dry ingredients: cassava flour, granulated sweetener, tiger nut flour, collagen, gelatin, cinnamon, baking soda and sea salt.
Add liquid ingredients: oil, milk, water and lemon juice, and stir to mix. I use an electric handheld mixer on medium speed until the mixture is combined.
Pour caramel over cranberries. It doesn't need to be perfectly evenly distributed.
Scrape down the sides of the mixing bowl with a spatula, and scrape/scoop batter into prepared baking dish. (Batter will be thick.) Use lightly wetted finger tips or wetted offset spatula to smooth top surface before baking. (Some of the berries may show through. The cake layer doesn't look very thick before baking.)
Bake 25 to 30 minutes, until browned all over and slightly puffed and the red berry juices are bubbly frantically around the edges.
Fully cool on rack. Slide knife around perimeter of cake to loosen any sticky spots. Hold serving plate over pan, and holding top of pan and bottom of plate, flip over. Remove pan, replace any loose cranberries that fall out. Slice, and serve.