Preheat oven to 425°F (for skillet) or 475°F (for ramekins). Place butter in a 10-inch cast iron skillet or oven-safe skillet and place in oven until butter melts. Swirl pan to coat sides. Or, divide butter among 8 (6 to 8 ounce) ramekins and place on a baking sheet. Place in oven until butter melts. Brush melted butter up sides of ramekins.

Meanwhile, place eggs, milk, flour, 3 tablespoons sugar, vanilla, lemon zest and salt in a blender and process 30 seconds or until foamy. When skillet (or ramekins) is hot and coated with butter, add batter (or evenly divide among ramekins) and place in oven. Bake skillet 20 minutes or until puffy and golden brown or ramekins 12 to 14 minutes.

Meanwhile, in a medium saucepan bring blueberries, lemon juice and remaining 4 tablespoons sugar to a boil over medium-high heat, stirring frequently. Reduce heat to medium-low and simmer 10 minutes or until mixture is thickened. Remove from heat, stir in strawberries and serve immediately with pancakes.