Preheat oven to 350F/180C for 15 minutes. Line cookie sheet(s) with parchment paper.

In a bowl combine together the flour, salt and cornstarch. Set aside.

In another large bowl, beat butter, sugar and vanilla using an electric mixer on medium speed, until light and creamy. This may take about 4-5 minutes.

On low speed, gradually add flour mixture, beating until blended. Using your hands, knead to form a smooth dough.

Now divide the dough into half and place it in two different bowls.

To one part of the dough add the cranberries and white chocolate chips. Knead well.

To the other half dough, add the blueberries and semi-sweet chocolate chips and knead well.

Scoop out tablespoonfuls of dough and drop it about 2 inches apart on prepared cookie sheet. You may choose to flatten the dough very lightly or just give it a quick roll and leave it as it is.

Bake in the oven for 13-18 minutes or until lightly browned around edges. Note that these cookies do not spread. Mine were done in 16 minutes.

Cool for 5 minutes on sheet, then transfer to a rack and cool completely.