Make the crust: Preheat the oven to 375 degrees F. Butter an 8-inch-square baking dish and line with nonstick foil, leaving an overhang on 2 sides. Lightly butter the foil.
Combine the flour, sugar and salt in a food processor and pulse to combine. Add the butter and pulse until the mixture looks like coarse meal. Add the lemon juice and pulse until the dough just comes together. Press the dough into the bottom of the prepared baking dish and bake until lightly golden, about 15 minutes.
Meanwhile, make the filling: Cook the bacon in a large skillet over medium heat, stirring occasionally, until crisp, about 8 minutes; drain on paper towels. Whisk the eggs, corn syrup, sugar, melted butter, vanilla and vinegar in a medium bowl until combined.
Scatter the pecans and bacon over the prepared crust, then pour in the filling. Bake until the filling is set and the nuts are golden brown, 30 to 35 minutes. Let cool completely in the pan on a rack, then lift out of the pan using the overhanging foil. Cut into squares and top with ice cream and more pecans.