Preheat oven to 450 degrees F. Lightly grease a 9x13 baking dish and set aside.

In a large bowl combine the flour, sugar, baking powder and salt. Cut in the butter until you have very coarse crumbs. (I like to either grate or cut my butter into small chunks and put in the freezer for about 5 minutes, so it is really cold) Stir in the milk just until dough is starting to leave the sides of the bowl.

Place contents of the bowl onto a work surface and with a light hand gently knead about 10 times. (This will help to finish mixing the dough and bring it all together) Roll out to 1/2 inch thick and fold into thirds (like a letter), turn it 90 degrees and roll out to 1/2 inch thick.

Fold into thirds and roll to 1 inch thick. Using a 3 inch biscuit cutter, cut as many biscuits as you can. You can re-roll and cut more biscuits if you like. (I always do, just do it gently). You will be using 8 biscuits for this recipe. Place the extras on a baking sheet and bake along with the casserole. You can serve them warm with butter and jelly!

Split the 8 reserved biscuits in half and place 8 halves in a lightly greased 9x13 baking dish. Bake for 10 minutes or just until they start to brown.

While the biscuits are baking begin by browning your sausage and onion in a large skillet over medium heat. Add in rosemary, salt, pepper and flour and stir well for 2 minutes. Carefully pour your cold milk or half and half into the pan while whisking. Continue to whisk to combine well. Cook and stir frequently until the gravy begins to thicken. Pour over baked biscuits. Top with remaining biscuit halves and sprinkle with cheddar. Bake for 20 minutes or until biscuits are browned.