Preheat oven to 400°F.
In a large skillet over medium heat, heat butter and onion until onion is translucent, about 3 minutes.
Turn heat to medium high and add in ground beef, garlic, and taco seasoning, stirring occasionally to break up the beef. Cook until lightly browned and no longer pink.
Turn heat back to medium and stir in tomato paste and cornstarch until fully mixed in. Add in half and half, tomato sauce, salt, and red pepper flakes. Cook for 5-10 minutes, until sauce has thickened and begins to bubble and pull away from the sides of the skillet.
Remove from heat and top with cheese. Arrange frozen tater tots in concentric circles around the skillet. Bake for 25-30 minutes, until taters are golden brown and cheese is fully melted.
Top with sour cream, cherry tomatoes, and green onions, and serve immediately!