Preheat the oven to 400˚F. Warm the butter and olive oil in a Dutch oven over medium heat. Add the diced onions. Saute for 4-5 minutes.
Add the sliced carrots, celery, and minced garlic. Saute for 2-3 minutes.
Stir in the flour, salt, pepper, dried thyme leaves, and ground sage. Cook while stirring for 2 minutes.
Pour in the chicken broth and add the diced potatoes. Stir until the flour clumps are dissolved. Then simmer for 10-12 minutes, stirring often, scraping the bottom.
Stir in the diced turkey, heavy cream, corn, and frozen peas.
Remove from the heat. Slice the biscuits in half and place them on top of the filling. Discard the remaining biscuit dough or use it for another purpose.
Bake for 18-23 minutes or until the filling is bubbly and the biscuits are golden brown.