Remove butterflied chicken breast from fridge and allow to come to room temperature, about 20 minutes; season on both sides with salt and pepper.
In a medium bowl, whisk egg and water until well-incorporated.
On a large plate, place flour and add a pinch of kosher salt and black pepper; whisk together with a fork; on a separate large plate, spread out Italian breadcrumbs.
Dredge chicken in flour, egg, and breadcrumbs – in that order – on both sides.
In a medium saucepan, add olive oil and butter and place on medium-high heat; once butter starts to melt, add chicken to pan.
Cook chicken until golden brown on both sides and cooked through, about 3 to 4 minutes each side.
Remove chicken from saucepan and place on a small sheet pan.
Spoon about 3 tablespoons of spicy marinara on top of chicken and then top each with a provolone cheese slice; broil on top rack in oven until cheese is melted, about 2 to 3 minutes.