>> source: Adapted from Sainsbury's Magazine & Claire Saffitz's technique
>> servings: 8
>> prep time: 30 minutes
>> cook time: 45 minutes
>> total time: 1 hour 45 minutes

In a large #bowl{}, mix @plain flour{200%g}, @icing sugar{20%g}, and a pinch of @fine sea salt{}. Add the cold @unsalted butter{100%g} (cut into 1/2-inch cubes).

Using a rolling pin, flatten the butter pieces into the flour right in the bowl, or press them between your fingers to create large, flat sheets of butter.

Mix @large egg yolk{1} with @ice-cold water{2%tbsp}. Pour it over the flour mixture. Toss with a fork until it starts to clump. If it feels too dry, add more @ice-cold water{1%tbsp}. Gather the dough, press it into a smooth disk, wrap tightly in plastic, and chill for at least ~{30%minutes}.

While the dough chills, cream soft @unsalted butter{60%g} and @golden caster sugar{60%g} together in a #bowl until light and fluffy. Beat in @large egg yolk{1} (or half a beaten egg), then fold in @ground almonds{60%g}, @ground cardamom{1/4%tsp}, and a pinch of @salt until you have a smooth, spreadable paste. Set aside at room temperature.

Preheat your #oven{} to 200°C (180°C fan / 400°F). Line a large, heavy #baking sheet{} with parchment paper.

Roll out your chilled dough directly on the parchment paper into a rough 12-inch (30cm) circle.

Spoon the cardamom frangipane onto the center of the dough and spread it into an even layer, leaving a clean 2-inch border all around the edge.

In a separate #bowl{}, toss @rhubarb{150%g} (sliced into 1/2-inch pieces on the diagonal), fresh @strawberries{150%g} (hulled and halved), 15 to 20 g of @caster sugar{20%g}, and @cornstarch{1%tbsp} together until the fruit is coated. Immediately pile the fruit right on top of the frangipane layer.

Fold the empty 2-inch border of dough up and over the outer edge of the fruit, pleating it as you go around.

Brush the pleated pastry border with beaten @egg{1} (for egg wash) and sprinkle it generously with @coarse demerara sugar{} for a crunchy finish.

Bake for 35 to ~{45%minutes}, until the pastry is a deep, dark golden brown and the juices are bubbling thickly.

While it bakes, simmer @sugar{40%g} and @water{2%tbsp} in a small #saucepan until it forms a light syrup. Remove from heat and stir in @vanilla extract{1/2%tsp}.

The minute the galette comes out of the oven, use a #pastry brush{} to gently paint the warm vanilla glaze over the baked strawberries and rhubarb. Let the galette cool on the baking sheet for at least 20 to ~{30%minutes} before slicing.