Add the milk and simmer gently until the liquid is almost evaporated, 25 to 30 minutes, stirring frequently.
Add the wine and reduce until evaporated, about 20 minutes longer. Then add tomatoes, paste and remaining salt, pepper and bay leaves. Simmer gently over medium-low heat until very thick, 3 to 4 hours. Stir often to keep the sauce from sticking. Remove bay leaves and cool to room temperature.
Set aside 3 cups Bolognese Sauce for serving. Spray a 13- x 10- x 2 1/2-inch baking pan with nonstick spray and spread 1/2 cup Bolognese on bottom of pan.
Lay 3 blanched pasta sheets side-by-side on the sauce. They should not overlap. They'll expand a little bit when the lasagna is baked. Top each sheet with a large spoon (about 3 tablespoons) of ricotta filling. Spread it over the sheets with the back of the spoon. Top with a layer of chard.
Spread with 3/4 cup Bolognese on the chard, it won't totally cover. Sprinkle with 1/4 cup of each cheese; repeat layering beginning with pasta then ricotta, chard, Bolognese and cheeses. Continue layering for a total of eight layers of pasta. Spread remaining ricotta over the last layer of pasta and sprinkle with remaining cheeses.
Bake the lasagna uncovered, for 40-45 minutes, until filling is bubbly and cheese melts. Rest 15 minutes. Reheat the reserved sauce while the lasagna rests. Cut the lasagna using the tip of a sharp thin knife. Serve with some of the reserved sauce and more parmesan cheese.