In a bowl, mix flour, cornmeal, a pinch of salt and baking powder for the dough. Mix it. Add sugar and mix again.
In a separate bowl, mix vegetable oil, kefir and egg.
Pour the liquid ingredients into the flour mixture.
Mix thoroughly (the dough turns out thick, does not drain from the spoon).
Add the mulberry and gently stir into the dough with a few strokes.
Fill out the cupcake forms (I got 10 pieces), send them to bake in a preheated 190 degree oven for 15-20 minutes. Focusing on the features of your oven, check the readiness with a wooden skewer.
Remove the finished cupcakes from the oven and let them cool.