Preheat the oven to 375 degrees and line a baking sheet with parchment paper. In a mixing bowl, combine the ground beef, mushrooms, half the Swiss cheese, egg, almond flour, garlic powder, salt, and black pepper. Mix just until evenly blended.
Divide the mixture into four equal portions and shape each into a small loaf. Place the loaves on the prepared baking sheet and press the remaining Swiss cheese on top of each one.
Bake the meatloaves for 25 to 28 minutes until the internal temperature reaches 160 degrees and the cheese on top has melted and browned slightly.
While the meatloaves bake, melt the butter in a large skillet over medium heat. Add the green beans and thyme, then cook for 6 to 8 minutes, stirring occasionally, until the beans are tender but still bright green.
Remove the meatloaves from the oven and let them rest for 3 minutes before serving alongside the green beans.