Preheat oven to 350°.
Spray an 8-inch cake pan with non-stick baking spray and line the bottom with a parchment circle.
In a large bowl, mix together the almond flour, baking powder, baking soda, cardamom, salt, and lemon zest. Set aside.
In a mixer bowl, cream together 6 tablespoons of the butter with the ½ cup granulated sugar until light in color. Scrape down the bowl and beat in the eggs 1 at a time until well-mixed. Add the vanilla.
Add the dry ingredients to the butter and egg mixture until well-mixed but taking care not to over mix. Stir in the skyr until smooth.
In a small sauce pan, heat the remaining 2 tablespoons of butter with the tablespoon of brown or granulated sugar and the saffron threads. Cook over medium heat, stirring, until bubbly and golden in color.
Pour the saffron mixture into the bottom of the prepared cake pan to evenly coat.
Arrange the peach slices in a circular pattern over the saffron mixture and then cover the slices with the cake batter.
Bake for 35-40 minutes until the cake is nicely browned and a tester inserted in the center comes out clean.
Cool the cake for about 15 minutes on a rack and then carefully invert it onto a round plate or platter so that the peaches are on the top.
Serve warm with a bit of whipped cream or ice cream if desired!