'I've made him a chocolate cake," my mother-in-law says as we walk through the door. My small son is sweaty and fractious. We've traveled four hours to get here, through bush fires and past smoke-belching lorries. It's a long way for a 19-month-old in the back of a hot car that's traveling slowly because of fuel shortages.
Chocolate cake should make him feel better.
Granny's cakes are always magnificent. In the early days of her marriage, her entry won the cake competition at a local agricultural show.
"I was so proud of her," Grandpa says beaming.
The secret (she told me as soon as I was married to her son) is the cooking oil you dribble in when the mixture is nearly ready for baking. It makes the cake nice and moist.
I think about my own granny and her cakes that I enjoyed back in England in the 1980s. It wasn't chocolate cake Grandma Chambers made for me and my sisters. It was Christmas cake. Even in June.
It was a two-hour drive to Grandma's bungalow from our home in Lincolnshire. We traveled across the slowly undulating hills of Leicestershire to the mining town of Coalville, where Grandma lived.
As soon as she heard our car pull into the driveway of her cottage, Chestnut Grove, Grandma hurried down the pathway to hug each of us.
"Come and have some cake," she'd say.
We tumbled into her living room, with its tweedy brown sofa and the small brass animals on the mantel over the fireplace. On the sideboard were our school portraits - my sister Sarah and I dressed in matching red high-necked pullovers and olive-green pinafores with chain stitching across the fronts.
Out of an old square tin came the Christmas cake, its icing slightly yellowed from waiting. Grandma never stinted on the sultanas. We munched chunks of it, washing it down with tumblers of orange squash.
She also told us stories of the past. "We had a dog then, a lovely black Labrador called Jock," she might say. "He sat out at the front of the house and guarded your daddy's pram. I knew I didn't have to worry, not with Jock there."
Back on the veranda in southern Africa, my son's mouth is smeared with chocolate icing. Somewhere, somehow on Zimbabwe's depleted supermarket shelves, Granny has managed to find some icing sugar.
Beyond the garden fence, two baboons grunt. This is my son's world. It is worlds away from Coalville.
Or maybe it isn't that far.
"I had custard and currants when I got home from school," my mother-in-law says as my son points to a croaking lourie bird in the muwanga tree. He looks a good deal happier than when we arrived.
"I had to do my homework straight away," my mother-in-law continues. "But it didn't seem nearly as hard, not with a cup of custard and an egg holder full of currants."
I think, how wonderful this is for a child: Granny's cake, served with a story.