Preheat a griddle to 350°.
In a medium bowl, combine the flour and baking powder.
In a large bowl, combine the ricotta cheese, milk, egg yolks and sour cream. Whisk until smooth. Stir in the chopped thyme, lemon zest, pecans and salt. Add the flour mixture, stirring until smooth.
In a large bowl, beat the egg whites with an electric mixer until stiff peaks form. Gently fold the egg whites into the ricotta mixture. Ladle about 1/3 cup of the batter for each pancake onto the hot griddle, or in a large nonstick skillet over medium heat. Cook the pancakes for 2 to 3 minutes, or until tops are covered with bubbles and the edges look dry. Turn, and cook on the other side. Repeat the procedure with remaining batter. Transfer to a serving platter and serve immediately with Thyme-Infused Syrup.
In a small saucepan, over medium heat, whisk the sugar and water together to combine. Add the thyme sprigs; then reduce the heat, and simmer for 3 minutes. Combine the cornstarch and 1 teaspoon of water in a small bowl until well mixed. Add the cornstarch slurry to the sugar mixture and simmer until thickened to a syrup. Remove from the heat, and strain into a serving bowl. Discard the thyme sprigs.
Yield: 2 cups