Pre-heat oven to 350F. Butter a 9-inch Springform pan (or a basic cake pan) and line with parchment paper.

You’ll need one stalk of rhubarb to decorate the top of the cake. Slice lengthwise into thin ribbons (¼-inch) and trim so it can fit inside the circle of your Springform or cake pan. Set aside.

With the remaining rhubarb stalks, slice into ½-inch slices (this will amount to a little over 1 cup of chopped rhubarb). Sprinkle with 1 tablespoon of sugar.

Whisk together flours, baking powder, cardamom (if using vanilla essence, add to wet ingredients later), and sea salt.

In a separate large bowl, with an electric mixer on medium, beat butter and sugar until fluffy, 3 minutes, add eggs one at a time, beating after each addition, (if using vanilla essence add now). Beat until well combined.

With mixer on lowest speed, add the dry ingredients, then sour cream (and vanilla essence, if using), then the rest of the dry ingredients. Beat until just combined.

With a spatula, gently fold in apples and rhubarb (discard any liquid that may have accumulated from the rhubarb).

Spoon batter into prepared pan, and smooth top (an offset spatula works well here).

Spread the reserved rhubarb stalks parallel to each other over the batter. Sprinkle with flaked almonds (optional).

Bake in the middle rack of the oven for 65-70 minutes, or until a tester inserted in center comes out clean.

Enjoy with powdered sugar on top, and a dollop of crème fraiche on the side.