The eggs cook from the residual heat of the pasta. When you pour the blended mixture into the hot orzo, the temperature is high enough to gently thicken and set the eggs the same way it would in a classic carbonara. You won’t see any scrambled pieces because the mixture is smooth, and the heat distributes evenly as you stir. The result is a creamy sauce that’s fully cooked without ever putting the pot back on the stove.