• Combine flour, pecans, sugar, baking powder, baking soda, and ½ teaspoon salt in a large bowl. Whisk together milk, sour cream, and 1 egg in a separate bowl. Stir milk mixture into flour mixture until just blended and smooth.
• Heat a griddle or large nonstick skillet over medium heat; butter. Pour about ¼ cup batter for each pancake onto griddle. Cook until tops are covered with bubbles and edges look dry, 3 to 4 minutes. Turn and cook until plump and cooked through, 3 to 4 minutes. Repeat with remaining batter.
• Slice each pancake in half and arrange, flat side down, in two snug rows in an 8-by-8-inch baking dish. Scatter half of the blueberries over the pancakes, tucking a few in between. Whisk together half-and-half, sugar, vanilla, cinnamon, remaining 4 eggs, and remaining ½ teaspoon salt in a bowl. Pour egg mixture over pancakes. Chill at least 4 hours and up to overnight.
• Preheat oven to 350°. Bake until puffed and set, 35 to 40 minutes. Let stand 10 minutes.
• Sprinkle with remaining blueberries and drizzle with Honey Sour Cream. Serve warm.

Honey Sour Cream

• Whisk together sour cream, half-and-half, honey, lemon zest, and a pinch ofsalt until smooth. Makes 1/2 cup.