Heat oven to 400 degrees F.

In mixing bowl combine flour, cornmeal, baking powder, salt, sugar and whisk a couple times.

Add lemon rind; combine.

In small bowl, whisk together heavy cream, vanilla extract, lemon oil (or juice) and egg until just combined.

Slowly add to flour mixture, while stirring. Add enough heavy cream (up to one cup) to hold ingredients together. You should not need more than one cup. Add blackberries and combine.

With clean hands, knead in bowl a few times until there is no more loose flour in the bowl and the berries are well-blended into dough.

Turn out onto lightly floured sheet of parchment paper; knead a couple more times to further combine. It's ok to press runaway berries back into dough. Shape into diagonal log about 3 inches wide and slice in diagonal pieces (see picture).

Place on baking sheet, slightly separate pieces and bake for 20-25 minutes until tops are golden brown.