Slow Cooker Banana Bread Pudding

Name: Slow Cooker Banana Bread Pudding
Ingredients: 16-ounce French brioche loaf, cut into 3/4-inch cubes ( 12 cups ); 1 tablespoon unsalted butter (softened); 8 large eggs; 4 cups half-and-half; 1/2 cup ( 100 g) granulated sugar; 1/2 cup ( 100 g) dark brown sugar , packed; 1 tablespoon pure vanilla extract (bourbon vanilla recommended); 1 1/2 teaspoons ground cinnamon; 1/4 teaspoon ground nutmeg; 1/4 teaspoon kosher salt; 3 medium ripe bananas , mashed; 1 cup ( 200 g) sugar; 1/4 cup water; 1/4 cup heavy cream; 4 tablespoons unsalted butter; 1/4 teaspoon cinnamon; 1/8 teaspoon salt