Preheat oven to 400 degrees Fahrenheit (200 degrees Celsius).
In a large skillet or Dutch oven, melt butter over medium heat. Add onion, carrots, celery, and potatoes. Sauté for 8-10 minutes until vegetables begin to soften.
Stir in minced garlic and cook for 1 minute until fragrant.
Whisk in flour and cook for 2 minutes to remove raw flour taste, stirring constantly.
Gradually whisk in vegetable broth and heavy cream. Simmer for 5 minutes until the sauce thickens.
Stir in frozen peas, corn, thyme, rosemary, salt, and pepper.
Transfer the vegetable mixture to a 9x13 inch baking dish.
Arrange the biscuits on top of the vegetable mixture in a single layer.
Bake for 15-20 minutes or until the biscuits are golden brown and the filling is bubbling.
Allow to rest for 5 minutes before serving.