3/4teaspoonsalt, reduce to 1/2 tsp if using salted butter
1 1/2teaspoonscinnamon
1/4teaspoonnutmeg
4Tablespoonsunsalted butter, at room temperature
1 1/2cupslight brown sugar, packed
1largeegg
3teaspoonsvanilla extract, or vanilla bean paste
1cupsour cream, full-fat recommended
4cupsrhubarb, fresh or frozen, diced
Topping:
1/3cupflaked almonds
1/3cupwhite sugar
1/2tspcinnamon
For Garnish:
Icing/Confectioners' Sugar, for dusting
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Instructions
Preheat oven to 350° F. (regular bake/not fan-assisted) and grease a 9 or 10-inch cake or springform pan. Line the bottom with a round of parchment (just to make your life easier, as this is a moist cake and it will just come out of the pan more easily). Set aside. *An 8-inch round pan isn't recommended as it wouldn't hold all the batter.
In a medium bowl, whisk together the flour, baking powder, salt, cinnamon and nutmeg. Set aside.
In a large bowl or the bowl of a stand mixer, beat the butter and brown sugar until it is well combined and resembles wet sand, about 2 minutes. Add the egg and beat until the mixture is well combined and there are no lumps of brown sugar. Add the sour cream and vanilla and beat to combine. *Take a moment to scrape down the bowl, especially under the beater, where unmixed brown sugar can hide sometimes. Beat again after scraping.
With the mixer on low, add the flour mixture and mix just until combined. Fold in the rhubarb with a spoon. Spoon the batter into the prepared pan.
In a small bowl, stir together the 1/3 cup white sugar and 1/2 tsp cinnamon for the topping, then sprinkle a bit over the cake. Scatter the flaked almonds on top and then sprinkle a bit more of the sugar mixture overtop. You don't need to use it all of the sugar mixture. Just use what feels like the right amount for you.
Bake in preheated oven until golden and a tester inserted in the centre comes out clean, 60-70 minutes, checking at about 50 minutes and if the cake is browned enough, lay a sheet of aluminum foil loosely over top to cook it longer without over-browning. If starting with frozen rhubarb, the cooking time could be as long as 70 minutes. Tip! Test often and be sure to test in several places near the centre of the cake. Sometimes the tester will hit rhubarb and not cake batter, making it seem done when it isn't.
Allow to cool in the pan for 5 minutes, then run a knife around the outside and carefully remove the outer ring. Transfer to a cooling rack (with the bottom part of the pan still on) and allow to cool until warm. Serve immediately or allow to cool completely, then remove the bottom part of the pan. This cake is nice served with a scoop of vanilla ice cream.
Notes
Be sure to read the notes above this Recipe Card where I share some valuable tips, options, substitutions and variations for this recipe! You'll also find step-by-step photos and a recipe video that you might find helpful.