Preheat the oven to 350°F (175°C). Line a 9 by 13-inch (23 by 33-cm) metal baking pan with parchment paper, leaving 1 inch (2.5 cm) of overhang. Spray the paper with vegetable oil spray. Line a baking sheet with parchment paper and set aside.
Melt 1 tablespoon of the butter in a medium nonstick pan over medium heat. Add the bacon and cook until the fat begins to render and the bacon turns a light golden brown, about 4 minutes. Add 2 tablespoons of the granulated sugar and the brown sugar and continue cooking until the sugar melts. Add the ¼ cup (30 g) finely chopped pecans and cook until the bacon and pecans are caramelized, about 3 minutes.
Using a slotted spoon, transfer the mixture to the prepared baking sheet and let cool for 10 minutes.
Put the remaining ¾ cup (170 g) butter and ¼ cup (50 g) granulated sugar in a bowl and, using a handheld mixer, mix until soft and creamy, about 2 minutes. Add the egg yolk and vanilla and mix until combined. Fold in the caramelized bacon and pecan mixture, then fold in the flour until moist crumbs form.
Press the crumbs into the prepared baking pan and bake on the middle rack in the oven until the crust is set and lightly browned, about 25 minutes.
While the crust is baking, whisk together the dulce de leche and sweetened condensed milk in a medium bowl until combined. Fold in the coconut, chocolate, and ½ cup toasted pecans and pour the mixture over the crust, spreading it evenly. Return to the oven and bake until the top is light golden brown, about 35 minutes. Let cool completely on a wire rack before cutting into squares or rectangles. The bars will keep, in a single layer in an airtight container, for up to 3 days at room temperature or up to 2 weeks in the freezer.