Preheat the oven to 350F, then prepare a 9 inch cake pan by coating it with butter.
In a medium bowl, sift together the flour, baking powder and salt.
In a stand mixer bowl, cream together the room temperature butter, yogurt, and orange zest. Slowly add in the sugar and blood orange oil and mix until light and fluffy.
Add in the eggs one at a time, making sure to scrape the sides and mix well between each addition.
Slowly ad in 1/3 of the dry mixture alternating between that and 1/3 of the orange juice. Beat well on low speed after each addition.
Layer the blood orange slices on the bottom of the 9-inch pan and lightly press on them. Pour the batter on top of the blood orange slices and bake for 45-55 minutes or until a toothpick or a knife inserted in the middle comes out clean!
Let the cake cool in the pan for 15-20 minutes then loosen the edges by running a knife between the cake and the edge of the pan. Invert on a cooling wrack to cool some more.
Serve this with whipped cream for a fancy tea time cake!