Place frozen chicken breasts in the bottom of a slow cooker. Add the chicken broth to the chicken and sprinkle with salt and pepper. Cover the chicken with foil.
Cut the top off the head of garlic to expose all the bulbs. Place in a piece of foil and add 1 tablespoon of olive oil on the exposed bulbs. Seal tightly and place on top of the foil covering the chicken in the slow cooker. Cook on low for 8 hours.
After roasted for 8 hours in the slow cooker, remove the foil packet containing the garlic. Open the packet and let the garlic cool slightly. Shred the chicken and place on a plate and cover with foil to keep warm.
Preheat oven to 450 degrees. Cover a baking sheet with foil or grease and sprinkle with cornmeal.
Melt butter and remaining olive oil in a small saucepan over medium heat.
Add flour, and whisk until well blended. Cook for 1 minute.
Slowly whisk in the milk and half and half. Squeeze the roasted garlic right out of the head of garlic by carefully squeeze the head from the bottom and work towards the top. All of the roasted garlic should squeeze right out into the white sauce. Mix in the pepper.
Cook for about 3 minutes, or until it starts to thicken. Remove from heat, and stir in Parmesan cheese.
Roll out dough into a thickness of approximately ½ inch and place on a prepared baking sheet. Spread white sauce over the dough. Top with chicken, red onions and cheese.
Bake for 17 minutes, or until the crust is golden, and the cheese is melted.
Remove from the oven, sprinkle with herbs. Cut and serve immediately.
Recipe by Becky's Best Bites at https://beckysbestbites.com/roasted-garlic-white-chicken-pizza/