110glight or dark brown sugarpacked (1/2 cup packed)
1/2teaspoonfine sea salt
1teaspoonground cinnamon
170gunsalted buttercold, cut into small cubes (12 tablespoons / 1 1/2 sticks)
120gpecansfinely chopped (1 cup)
Sweet potato filling
450gcooked, mashed sweet potatocooled (about 1 lb; from 2–3 medium sweet potatoes)
60gunsalted buttermelted and slightly cooled (4 tablespoons / 1/4 cup)
1cansweetened condensed milk(396 g / 14 oz)
2largeeggsroom temperature
1teaspoonground cinnamon
1/8teaspoonground nutmegfreshly grated if possible
1/4teaspoonfine sea salt
1/2teaspoonvanilla extract
1/2teaspoonorange zestfinely grated (optional)
To finish (optional)
lightly sweetened whipped creamfor serving
Instructions
Preheat the oven to 175°C / 350°F with a rack in the center. Lightly grease a 23×33 cm / 9×13 inch metal baking pan and line it with parchment so the paper overhangs the long sides.
In a large bowl, whisk together the flour, granulated sugar, brown sugar, salt, and cinnamon until no lumps of brown sugar remain. Add the cold butter cubes and cut them into the dry ingredients until the mixture looks like damp sand with some pea-sized bits of butter.
Stir in the chopped pecans. Scoop out about 1 heaping cup of the crumb mixture (roughly 150–170 g) and set it aside for the topping; the rest will form the base crust.
Press the remaining crumb mixture firmly and evenly into the bottom of the prepared pan (use fingers or the flat bottom of a measuring cup). Bake for 12–15 minutes, until the edges look slightly golden and the surface looks set but not browned.
Remove the pan from the oven and reduce the oven temperature to 165°C / 325°F. Let the crust cool on a wire rack for 5–10 minutes so it’s warm but not piping hot.
In a medium bowl, whisk the mashed sweet potato until smooth. If needed, push it through a sieve or use a food processor for a silkier texture.
Whisk the melted butter into the sweet potato, then whisk in the sweetened condensed milk until glossy and uniform.
Beat the eggs lightly in a separate bowl, then whisk them into the sweet potato mixture. Add cinnamon, nutmeg, salt, vanilla, and orange zest (if using) and whisk just until smooth and evenly combined.
Pour the filling over the slightly cooled crust. Tilt the pan or use an offset spatula to spread it into an even layer, nudging into the corners.
Break up the reserved pecan crumb mixture into small clumps and loose crumbs and sprinkle evenly over the filling.
Bake at 165°C / 325°F for 30–35 minutes, until edges are slightly puffed, topping is lightly golden, and the center jiggles slightly but doesn’t slosh when gently shaken.
Cool the pan on a wire rack to room temperature, at least 1–2 hours. For clean slices, cover and refrigerate for another 2 hours (or up to overnight) before cutting.
Lift out using the parchment overhang, transfer to a cutting board, and cut into 12–16 bars with a long sharp knife (wipe between cuts). Serve chilled or at cool room temperature, with whipped cream if desired.