Heat the olive oil in a large pot over medium heat. Add the pork cubes and cook until browned on all sides, about 6 minutes. Remove the pork and set it aside.
Add the sliced mushrooms and diced onion to the same pot. Cook until the mushrooms release their liquid and the onion softens, about 5 minutes. Stir in the minced garlic and cook for 1 minute more.
Sprinkle the flour and dried thyme over the mushroom mixture. Stir well for 1 minute to coat everything evenly.
Slowly pour in the chicken broth while stirring to avoid lumps. Return the browned pork to the pot and bring the mixture to a simmer. Cover and cook for 25 minutes, stirring occasionally.
Stir in the heavy cream, then add the frozen mixed vegetables and frozen peas. Simmer uncovered for 8 minutes until the vegetables are heated through and the sauce thickens slightly. Season with salt and black pepper to taste before serving.