In a 2-cup liquid measure, dissolve yeast and 1 teaspoon sugar in warm water. Let stand until foamy, about 5 minutes.
Insert dough blade in work bowl; add bread flour, whole wheat flour, 2 teaspoons sugar and salt. Process to combine, about 20 seconds. Add cold water and olive oil to yeast mixture. With machine running, pour mixture through feed tube in steady stream, only as fast as flour absorbs it. Continue processing until dough cleans inside of work bowl and forms a ball. Knead dough by processing an additional 45 seconds. Open lid to check dough consistency. If dough is stiff and somewhat dry, add 1 teaspoon water; if soft and sticky, add 1 tablespoon flour. Close lid and process for 10 seconds. Check dough consistency again, making additional adjustments if necessary.
