Step 1

Whisk together flour, sugar, and salt in a medium bowl. Add butter, and toss to coat. Using your fingers, smear and work butter into flour mixture until it forms pea-size pieces. Add 2 tablespoons cold water; stir with your hands to form a shaggy dough. Gently knead to bring dough together. Shape into a 1-inch-thick disk. Wrap tightly in plastic wrap; chill at least 2 hours or up to 2 days.

Step 2

Meanwhile, toast chia seeds in a small skillet over medium, stirring often, until fragrant and glossy, 2 to 4 minutes. Transfer to a small bowl, and let cool until ready to use.

Step 3

Turn dough out onto a lightly-floured surface. Roll into a 9-inch circle. Sprinkle dough evenly with chia seeds, and continue rolling, pressing seeds into dough, to form an 11-inch (about 1/8-inch-thick) circle. Fit dough into a 9-inch round tart pan with a removable bottom. Trim edges of dough, and discard scraps. Use a fork to prick bottom of tart shell. Freeze tart shell at least 30 minutes or up to overnight.

Step 4

Preheat oven to 350°F. Line tart shell with parchment paper, and fill with pie weights or dried beans. Bake in preheated oven until set, about 30 minutes. Remove parchment and weights, and bake until shell is lightly browned, 10 to 12 minutes. Let cool completely on a wire rack, about 30 minutes.

Step 5

Whisk together sugar, lemon juice, egg yolks, eggs, cornstarch, and salt in a small saucepan until smooth and well combined. Cook over medium-low, whisking constantly, until curd just begins to bubble and is very thick but pourable, 8 to 10 minutes. Remove from heat, and whisk in butter, olive oil, and lemon zest until well combined.

Step 6

Pour mixture into cooled crust, and press plastic wrap directly onto surface. Chill until set, at least 4 hours or up to 8 hours or overnight. Remove plastic wrap, and garnish with toasted pine nuts just before serving.