In a mixer with a dough hook, combine the milk, water, saffron, and yeast.Let it rest for 5 minutes, then mix to dissolve the fresh yeast.Add the eggs, flour, oil, sugar, and salt, and mix for about 5 minutes at low speed (the dough will be sticky).Stir in the diced ham, chopped green onions, and grated Swiss cheese.Transfer the dough to a greased bowl, cover, and refrigerate overnight.Put the dough on a lightly floured surface and cut it into 12 equal pieces.Shape each piece into a ball and place them in a greased 12-cup muffin tin.Cover loosely and let rise for 1 hour.Preheat the oven to 350°F (180°C).Brush the tops of the brioche with the egg wash and place thin slices of Swiss cheese in a cross pattern on each brioche.Bake for 25-30 minutes, until the tops are golden brown.Let cool for 15 minutes in the tin, then transfer to a wire rack to cool completely.