Chop the garlic, onion, and bacon. In a hot pan, render the bacon until crisp, then remove and set aside for topping. In the same pan, stir the garlic and onion until soft.
Add the tomato paste and cook through for 2 minutes.
Add the tequila and flambe to cook off the alcohol. Pour in the cream and stir with the parmesan; once combined, swirl through a little more cream.
Add the cooked pasta with a splash of pasta water and mount with the cold butter. Top with the reserved bacon and more parmesan, and serve.