Combine the thawed orange juice concentrate with about 10 ounces water (add enough water just to the 2-cup fill line).
Add orange zest to orange juice, and heat in the microwave until hot. Set aside to cool down, (I placed it into the refrigerator while I creamed butter/sugar).
Cream butter, sugar, and salt until light and fluffy (about 5-8 minutes).
PREHEAT OVEN TO 350F (PYREX).
Add eggs one at a time, mixing well after each.
Add orange (or vanilla) extract. Mix until combined.
Pour COOLED, BUT STILL WARM, orange juice over the flour mixture.
Add butter, sugar, salt, egg mixture IMMEDIATELY to flour/orange juice mixture. Combine well.
Immediately pour cake batter into a 13 x 9 Pyrex dish sprayed with baking spray containing flour, and bake 20-25 minutes. (Check at 20 minutes).
While hot, I poked holes all over the cake with a wooden skewer, then topped the cake with hot Cooked Fudge Frosting (Cooked Fudge Frosting