Line an 8.5x4" loaf pan with parchment and grease with either baking spray or butter and flour. Set aside.
Sift your cake flour into a bowl, set aside.
In the bowl of your stand mixer, measure your sugar out. Zest your orange into the sugar, and then rub the zest into the sugar between your fingers. This will release the oils into the the sugar and impart a much stronger orange flavor. The sugar will begin to turn a yellow orange color and feel slightly damp.
Add your butter to your orange sugar. Using the paddle attachment, beat your butter and sugar together for about 5 minutes on medium speed until it is well combined, light and fluffy.
Add 1 egg at a time, mixing each thoroughly (for about 90 seconds) into the batter for a total of 3 eggs and 1 yolk.
Add in your extract and mix in for another 30 seconds.
Add in half of your flour and your salt into the batter and mix on low until combined.
Add your heavy cream, and mix, then add the remainder of the flour. When the flour has been mixed in, turn your mixer to medium high and mix for at least 5 minutes. When your batter is ready it will be smooth and silky looking.
Spoon batter into your prepared loaf pan and smooth out the top. Gently bang on the counter once to release any air pockets.
Place your cake into your COLD oven, and turn on to 350°F. Bake for 60-70 minutes, making sure a skewer or toothpick comes out clean.
Let cake cool in pan for 30 minutes, then remove from pan and place on cooling rack to cool completely.
