Preheat your oven to 400 degrees Fahrenheit.
In a large mixing bowl, combine low sodium cream of chicken, low sodium cream of mushroom, and mascarpone cheese. Mix until well combined.
Next, fold in the broccoli florets, cheddar cheese, and black pepper. Ensure the broccoli is well coated with the creamy mixture.
Transfer this mixture into a rectangular or oval casserole dish (approximately 8 by 12 inches). Spread it evenly.
In a medium bowl, whisk together the all-purpose flour, baking powder, baking soda, and salt.
Grate the cold butter into the flour mixture. Transfer the bowl to the freezer for five minutes.
Meanwhile, combine the buttermilk and egg in a bowl, and beat until combined.
After five minutes, take the bowl out of the freezer and mix the butter into the flour until it resembles small peas.
Add the grated cheddar cheese to the flour mixture and mix well.
Pour the buttermilk mixture into the dry ingredients and mix until just combined.
Lightly knead the dough until it forms a solid mass. Using two tablespoons, drop mounds of dough on top of the filling.
Top with more cheddar cheese and freshly ground pepper.
Transfer the casserole to the oven and bake for 40 to 45 minutes until the biscuits are golden brown.
Carefully serve by removing a biscuit and spooning out the filling.