Put the bacon in a medium saucepan over medium heat and cook, stirring, until very crisp, about 10 minutes. Remove with a slotted spoon and drain on paper towels, reserving the fat in the pan.
Add the brown sugar, corn syrup, beer, butter, heavy cream and a pinch each of kosher salt and pepper to the pan. Bring to a boil, then reduce the heat to medium low and simmer until slightly thickened, 6 to 8 minutes. Transfer to a bowl and refrigerate until ready to serve.
Scoop the ice cream into bowls and spoon the toffee sauce on top. Garnish with the crispy bacon bits, toasted pecans and sea salt.