Slice the peppers in half vertically and remove the stem, seeds, and the white membrane.
Place the peppers in a 9x13 inch baking pan and bake for 15 minutes, or until the desired tenderness.
While the peppers are baking, slice the onion and sauté it with the butter in a skillet over medium heat until golden and caramelized. Scoop the onions out into a dish and set aside for now.
Cook the ground beef in the same skillet until browned, breaking it up a bit as it cooks.
When the beef is browned, add in the salt, pepper, Worcestershire sauce, and Tabasco sauce. Stir well.
Add in the onions and stir to combine.
When the peppers are done baking, use a paper towel to blot out any liquid that may have pooled inside them. Then spoon the meat mixture into the peppers.
Top each pepper with a slice of the Swiss cheese.
Pop the baking pan back into the oven for just a couple more minutes to let the cheese get all melty and bubbly.