Preheat oven to 350 degrees F.

To make topping, melt butter in a small saucepan, and add the brown sugar, ½ the orange zest and juice, ½ teaspoon cardamom, ginger, and salt. Heat and stir until sugar is completely dissolved and mixture begins to bubble around the edges. Pour sugar mixture into a 9-inch springform cake pan, swirling or brushing to coat pan evenly.

To prepare cake, trim rhubarb stalks to snugly fit into a pan and arrange on top of brown sugar to cover the base.

Whisk together the flour, baking powder, cardamom, and salt in a medium bowl. In a separate small bowl, stir together yogurt and remaining orange juice and zest.

In the bowl of a stand mixer or in a large bowl using a hand mixer, beat butter and both sugars until pale and fluffy. Beat in the eggs, 1 at a time, until fully incorporated. Beat in vanilla extract.

Fold flour mixture and yogurt mixture into butter mixture ⅓ at a time, alternating back and forth, beginning and ending with flour. Blend in the pistachios. Pour the resulting batter into the pan, on top of rhubarb stalks, and smooth the top. Bake in oven for 1¼ hours. The top should be browned and the edges bubbly. A cake tester inserted in the center should be clean.

Cool cake for 5 minutes then run a small sharp knife around edges. Place a plate on top of the cake pan and invert. Slowly lift the cake pan away. Cake is best served warm with freshly whipped cream or vanilla ice cream. Store leftovers in an airtight container at room temperature for up to 3 days