1. Preheat oven to 375°. In small saucepot, heat blueberries and 1 tablespoon granulated sugar over medium heat 3 minutes or until blueberries burst. Reduce heat to medium-low; cook and stir 7 minutes or until reduced to about 1/3 cup. Remove from heat; cool to room temperature.

2. Spray 10-inch, high-sided oven-safe skillet with nonstick baking spray. In medium bowl, with mixer on medium-high speed, beat butter and 1/4 teaspoon salt 5 minutes or until light and fluffy; add blueberry mixture and beat 1 minute or until smooth. Makes about 3/4 cup Blueberry Butter.

3. In large bowl, with mixer on high speed, beat egg yolks 3 minutes or until pale yellow and thickened slightly. Add milk; beat 30 seconds or until smooth. Add flour and 1/4 teaspoon salt; beat 15 seconds or until almost smooth.

4. In separate large bowl, with mixer on medium-high speed, beat cream of tartar, vinegar and egg whites 3 minutes or until stiff peaks form, gradually adding remaining 3 tablespoons sugar each minute. Gently fold egg white mixture into egg yolk mixture; do not overmix. Makes about 6 cups.

5. Gently transfer batter to prepared skillet; bake 20 minutes or until puffed and golden brown. Cut pancake into 8 wedges.

6. Serve pancake topped with Blueberry Butter, and dusted with powdered sugar and/or garnished with blueberries along with maple syrup, if desired.

Approximate nutritional values per serving (1 pancake wedge, 1 tablespoon Blueberry Butter): 224 Calories, 16g Fat, 8g Saturated Fat, 148mg Cholesterol, 193mg Sodium, 16g Carbohydrates, 1g Fiber, 9g Sugars, 6g Added Sugars, 5g Protein