Preheat the oven to 375 degrees F (190 degrees C).

Unroll each crust into two 9-inch pie pans.

Heat oil in a large skillet over medium heat. Cook celery, onion, and garlic in the hot oil for 1 to 2 minutes. Add sausage, breaking apart to brown; sprinkle in sage and continue browning until no longer pink, 5 to 7 minutes. Remove from heat. Add cottage cheese and mix well.

Divide meat mixture evenly and spoon into each of the two pie crusts.

Whisk eggs, milk, tarragon, salt, and pepper together in a mixing bowl. Pour egg mixture over meat mixture in the pie crusts. Sprinkle Cheddar-Jack cheese over the tops.

Bake, uncovered, in the preheated oven on the middle rack until tops are puffed and golden brown, about 40 minutes. Remove from the oven and let stand for 5 to 10 minutes before slicing.