Looking every bit as French as his name suggests, Mark Courseille, the pastry chef at Michel by Michel Richard in the Ritz-Carlton Tysons, sets some high standards with his elegant desserts. Considering that his father was a physics teacher, dealing with sophisticated sugary treats seems like an unusual career choice. But learning about his childhood clears up some puzzles. A native of Bordeaux, Courseille talks about his grandmother, who not only worked in a farmers’ market selling cheese but who also was an accomplished home-schooled pastry maker. “I went to market with her often,” he said. “I used to love it. When I was a kid, I was really interested in good food, and I used to make good sauces.” And one of his early culinary triumphs was to excel in roasting duck breast.