Blueberry-Sausage Strata

1/2 lb sweet Italian turkey sausage links, casing removed
2 leeks, cleaned and thinly sliced-white and light green parts only
1 T. chopped fresh thyme
4 c. fresh blueberries
1 {1 lb} loaf whole wheat crusty bread, torn into small chunks
1 quart low-fat 1 % milk
1-1/2 fat free egg substitute-or 9 egg whites+3 whole eggs
1/2 t. kosher salt
1/4 pepper

Spray large nonstick skillet with cooking spray and set over med-high heat. Add sausage, leeks, and thyme; cook, breaking up sausage with wooden spoon about 4 minutes. remove skillet from heat; stir in 2 cups berries. Spray 9x13 inch baking dish with cooking spray. Whisk milk, egg substitute, salt and pepper in large bowl until well blended. Place half of bread in baking dish; top evenly with sausage mixture and then egg mixture. Top with remaining bread, pressing it into egg mixture until moistened. Cover and refrigerate overnight. Preheat oven to 325 degrees F. Uncover and place in large roasting pan. Add enough hot water to come up half way up the sides of baking dish. Bake until center is set and top is browned, 60 to 65 minutes.
Carefully transfer strata to rack and let cool. Serve with remaining blueberries and a little syrup if desired.