In another bowl, cream the butter and brown sugar with an electric mixer. Add the eggs one at a time, whisking until smooth. Add the sour cream and mix well. With the machine running on low speed, stir in the dry ingredients alternating with the honey mixture. Spread the batter out in the Bundt pan.
Bake for 50 minutes or until a toothpick inserted in the centre of the cake comes out clean. Let cool for 10 minutes. Turn the cake out on a wire rack. Freeze at this point, if desired (see note). Place the wire rack over a baking sheet.
Syrup and Confit Plums
Meanwhile, in the same pot, bring the brown sugar, water, honey and salt to a boil just until the brown sugar has dissolved.
Using a pastry brush, cover the warm cake with 1/2 cup (125 ml) of the brown sugar syrup. Let cool for 1 hour.
Meanwhile, pour the remaining syrup into a 13 x 9-inch (33 x 23 cm) baking dish. Add the plum wedges and orange zest. Mix well. Bake for 35 minutes or until the plums are tender and the juice is thick and syrupy. Let cool for 30 minutes. The plums will keep for 2 weeks in an airtight container in the refrigerator.
Serve the cake warm or cold with the confit plums, yogurt or ice cream, and a drizzle of honey. The cake will keep for 3 days, covered, at room temperature.
Note from Ricardo
Let the cake thaw completely before brushing it with the syrup.
