Heirloom Tomato Pesto Galette

Ingredients (9)

• 1 3/4 cups all-purpose Gold Medal flour
• 1 tablespoon granulated sugar
• 1/4 cup coarse cornmeal
• 1/4 teaspoon salt
• 1/2 cup cold butter
• 1/3 cup buttermilk
• 3 large heirloom tomatoes
• 1/3 cup basil pesto
• 1 egg