Mushroom and Sausage Pot Pie With Biscuit Topping 4 Steps
Prepare the biscuits: Mix the all-purpose flour, baking powder, sugar and kosher salt together. Grate the cold butter and work it into the dry mix with your hands. Add whole milk and stir gently with a fork to bring it all together. Turn dough out onto a clean counter, fold it over a few times by hand to get it into a 1-2 inch thick layer and using a cutter or rim of a glass about 2 ½" in diameter cut between 8-10 biscuits (any leftover trim can be quickly reworked by hand to form a biscuit as well). Transfer to a parchment-lined baking sheet, wrap well and freeze for 4 hours or overnight until ready to bake.
Heat a large oven proof shallow braiser or saute pan on medium high heat, add in olive oil and the sausage and begin browning. Break up the sausage into chunks using a wooden spoon until most of the sausage is deeply browned (no need to worry about cooking the sausage through entirely as it will continue to cook when baking). Remove the sausage from the pan and turn the heat down to medium.
Add in the sliced celery as well as the sliced onions and cook until vegetables are beginning to soften. Add in the unsalted butter, mushrooms and begin cooking until the mushrooms just begin to soften. Add in the minced garlic as well as the all-purpose flour and cook for another 2 minutes. Deglaze with the white wine, simmer until almost all of the wine has evaporated. Add in the chicken stock and whole milk and bring just to a simmer. Add in the frozen peas, thyme leaves and chopped sage and browned sausage. Adjust seasoning with kosher salt and black pepper.
If not using an oven safe pan, transfer the filling to a casserole or baking dish. Top with the frozen biscuits, making sure to leave about 1-2 cm of space between each biscuit. Brush the top of the biscuits with melted butter and bake in a preheated 425°F oven for 30-35 minutes until bubbly and the biscuits are evenly browned and cooked through. Allow to stand for 5 minutes before serving.