For another variation on the theme of fruits-that-aren’t-lemons- appropriating-the-form-of-lemon-bars, this one features rhubarb.

Method:

• Preheat the oven to 180°C. Grease a 23-cm (9-inch) square metal baking pan and line with enough baking parchment to allow for 2-cm (1-inch) wings on opposite sides. (If you only have a glass or ceramic pan, that’s okay; just prepare to bake these a little longer!)
• In a food processor, pulse together the plain (all-purpose) flour, almond flour, granulated sugar, and salt. Scatter on the butter and pulse until pea size. Add the egg white and rosewater and continue to pulse until the mixture starts to clump together. (You can also do this by hand in a big bowl. Use your fingers to incorporate the butter by smashing and rubbing it in with the dry ingredients until it’s evenly dispersed and the butter is pea size.
• Add the egg white and rosewater and use a rubber spatula to gently mix into a shaggy mass.)
• Transfer the dough to the prepared pan and press evenly all around the bottom. Bake until the crust is lightly golden; begin checking for doneness at 15 minutes.
• Reduce the oven temperature to 160°C (325°F).
• To make the filling, place the rhubarb in a medium saucepan and add water just to cover (about 360g / 1 ½ cups) and 50g (¼ cup) of the granulated sugar. Scrape in the vanilla bean seeds and drop in the pod (or add the paste, if using). Simmer until the rhubarb is falling apart, about 10 minutes. Cool briefly, just so it’s not hot, then strain and discard the solids.
• In a medium saucepan, whisk together the remaining 250g (1 ¼ cups) sugar, the cornstarch, and salt. Add the eggs and egg yolks and whisk until smooth. Whisk in the lemon juice and 180g (3/4 cup) of the rhubarb juice. (Keep any extra rhubarb juice to sweeten iced tea or cocktails.) Cook over medium heat, whisking continuously, until the mixture begins to simmer and thicken and bubbles pop to the surface, 7 to 10 minutes. Remove from the heat and whisk in the lemon zest, then the butter and coconut oil a little at a time, whisking until melted and the mixture is smooth. Whisk in just enough food colouring to make the mixture a salmon-pink color, a couple of drops.
• Pour the filling mixture over the cookie crust (it’s totally okay if the crust is still a little warm; you just don’t want it to be piping hot) and bake until the edges are set but the centre is just a tiny bit jiggly; begin checking for doneness at 25 minutes. Let cool completely in the pan. To get the cleanest cuts, refrigerate for a few hours until cold.
• Dust with icing (powdered) sugar and then with a sharp knife, cut into 16 squares, wiping the blade after each cut.
• Store, refrigerated, an airtight container between layers of baking parchment for up to 3 days.

Recipe extracted from Sweet Farm (Cookies, Cakes, Salads (!), and Other Delights from My Kitchen on a Sugar Beet Farm (William Morrow)