- 3/4 cup (175 mL) all-purpose flour
- 1/2 cup (125 mL) ground almonds
- 1 tbsp (15 mL) granulated sugar
- Grated rind of 1 lemon
- 1 tsp (5 mL) grated orange rind
- 1/2 tsp (2 mL) nutmeg
- 1/4 tsp (1 mL) ground ginger
- Pinch salt
- 1/2 cup (125 mL) cold unsalted butter, diced
- 1 egg yolk
- 3/4 tsp (4 mL) vanilla
- Lemon Filling:
- 5 eggs
- 3 egg yolks
- 1 cup (250 mL) granulated sugar
- 3/4 cup (175 mL) lemon juice
- 2 tbsp (30 mL) butter
- Rhubarb Topping:
- 1 lb (500 g) fresh rhubarb, chopped, or 5 cups/1.25 L frozen chopped rhubarb
- 1/2 cup (125 mL) granulated sugar
- Two 3-inch/8 cm strips orange rind
- 1/2 cup (125 mL) strained orange juice
- 1 tsp (5 mL) gelatin
Lemon Filling: In top of double boiler, or in heatproof bowl over pan of hot (not boiling) water, whisk together eggs, yolks, sugar and lemon juice; cook, stirring often, until thick enough to mound on spoon, 15 to 20 minutes. Stir in butter. Strain through fine sieve into bowl. Place plastic wrap directly on surface; refrigerate until cold, about 2 hours.
Meanwhile, in food processor, pulse together flour, almonds, sugar, lemon and orange rinds, nutmeg, ginger and salt. Pulse in butter until fine crumbs are formed; pulse in egg yolk and vanilla. Pulse in about 1 tbsp/15 mL cold water or just enough to allow dough to come together when pressed. Form into disc. Chill for 30 minutes (or for up to 1 day).
On lightly floured surface, roll dough out to 11-inch/28 cm circle; fit into 9-inch/23 cm, 1-1/2 inch/4 cm deep tart (quiche) pan with removable bottom. Trim to 1-inch/2.5 cm overhang; fold down inside rim, pressing lightly against side of pan to make slightly raised edge. Refrigerate for 30 minutes.
Prick bottom of pastry shell all over with fork. Line with foil; fill with pie weights or dried beans. Bake in bottom third of 400F/200C oven until top of rim starts to turn golden, 15 to 20 minutes. Remove weights and foil; bake until golden, about 10 minutes. Let cool on rack.
Spoon lemon filling into pie shell, smoothing top. Bake in bottom third of 325F/160C oven for 12 minutes. Let cool on rack. Refrigerate until cold, about 2 hours.
Rhubarb Topping: In saucepan over medium-low heat, simmer rhubarb, sugar, and orange rind and juice until rhubarb is tender, about 6 minutes. Strain over bowl to catch juice; remove orange rind and let rhubarb pieces cool.
Pour 3/4 cup/175 mL of the reserved juice into small saucepan; sprinkle gelatin over juice. Let stand for 5 minutes. Stir over low heat until gelatin is dissolved. Let cool slightly.
Arrange cooled rhubarb pieces over tart. Pour gelatin mixture evenly over top. Refrigerate until set, 2 to 3 hours.
Makes 8 to 10 servings.