Prepare sous vide water bath at 140 degrees Fahrenheit.
Butterfly two chicken breasts.
Place chicken breast between two sheets of plastic wrap. Using flat side of meat tenderizer, flatten chicken down to ¼ inch thickness.
For the pesto, combine basil, spinach, Parmesan, olive oil, garlic, and salt in a food processor or blender. Pulse and scrape down sides to ensure all ingredients are thoroughly incorporated.
Divide the pesto mixture between the two butterflied chicken breasts. Evenly distribute mixture on top of each breast.
Roll up the chicken breast, starting at the narrowest edge and fold over like a jelly roll, enclosing the pesto as you go.
Roll chicken roulade in multiple layers of plastic wrap (10-15) and secure each end by tightly twisting.
Place chicken roulade in sous vide water bath for 1.5 hours.
Remove chicken roulade from water bath and remove plastic wrap.
Place chicken roulade under the oven broiler on high for several minutes to get a golden color on the outside.
Let meat rest 5-10 minutes and slice into 1-inch pieces to serve.