Butterfly the chicken breasts: Slice the chicken breasts in half lengthwise (butterflied) to get two thinner pieces from each breast.
Prepare the dredge: Combine the eggs with salt and pepper in a shallow bowl. In another bowl combine the ½ cup cornstarch with the flour and mix well.
Dredge the chicken: Dredge the chicken through the egg first, then through the flour mixture.
Fry chicken in batches: Heat the olive oil in a large skillet over medium heat. Add the chicken to the skillet, as many as you can fit, and fry for 3 to 4 minutes on each side or until golden and crispy. Transfer the chicken to a paper towel lined plate and repeat with remaining chicken.
Make the lemon sauce: Drain any leftover oil from the skillet. Add the butter to the skillet and melt. Add the lemon juice, sugar, chicken broth, ¼ tsp salt and 1 tbsp of cornstarch. Whisk everything well together and cook until the sauce has thickened and is smooth.
Finish the dish and serve: Slice the chicken into thin strips and pour lemon sauce over. Serve with rice.