Cake:

First, preheat the oven to 350℉. While preheating, butter a 9 to 10 inch springform pan, and line the bottom with parchment paper.

Grind the orange and lemon zest and the 1 1/2 cups sugar together in a food processor until finely ground. Place this in a stand mixer and add the butter. Beat until well combined.

Grind the almonds, flour and salt together in the food processer, until the almonds are finely ground.

Take half of the almond mixture and add to the butter. Slowly begin adding the eggs, stopping occasionally to scrape the sides of the bowl. Now add the other half of the almond mixture.

Add batter into pan, making sure to level the top of the batter. Place in oven and bake for 40 minutes. Check batter by poking a toothpick in the center and checking to see if it comes out clean, however still moist. 
 

Syrup: 

Heat the 3/4 cup orange and lemon juice and the 6 tbsp of sugar in a saucepan until boiling, then set aside.

Once the cake comes out of the oven, brush the syrup liberally onto the hot cake, and let it cool completely in the pan.

Candied Orange Slices:

Take the organic orange (or unsprayed orange) and cut into 1/4 inch thick slices. Place the slices in a saucepan and add water until it covers them. Bring to a simmer, and blanch the slices for 10 minutes and drain. 

Place the oranges back in the saucepan and add the 2/3 cup sugar and 2/3 cup water. Bring to a simmer and cook for 10 minutes, or until the slices are translucent and tender.

Once done, place the candied orange slices on top of the cake and serve.