Cover chicken breasts with plastic wrap or waxed paper and pound to an even thickness, about 3/4-inch.
In a medium bowl, whisk together flour, garlic salt, and pepper. Dredge each chicken breast in flour mixture.
Whisk together eggs and water and place in a shallow dish or plate. Dip each dredged chicken breast in the egg.
In a large skillet, heat olive oil over medium-high heat until shimmering.
Add each chicken breast to the hot oil and cook for 2-3 minutes per side.
Remove chicken and set aside to keep warm. Add lemon slices to the pan juices. Cook for a minute or so per side.
Add lemon juice, chicken stock and white wine to the skillet and bring to a boil. Whisk occasionally to loosen brown bits. Cook for 3-4 minutes to cook off some of the wine.
Place butter in remaining flour mixture and turn to coat. Add flour covered butter to the skillet and allow to melt down, stirring occasionally to combine flour with sauce. Whisk and cook for 3-5 minutes, or until sauce thickens.
Add chicken back to the sauce in the skillet and heat through, about 2-3 minutes.