Slow Cooker Veggie Pot Pie

veggies chopped into bite sized pieces as needed (I used: brussels sprouts, frozen corn kernels, frozen peas, diced potatoes, baby carrots, and pre-sliced mushrooms)

diced onion

minced garlic

sprigs fresh thyme (leaves removed)

flour

chicken broth

cornstarch

heavy cream

salt and pepper

frozen puff pastry sheet (thawed)

butter