Strawberry Cookie Bars (Tertiy Pirog)

Bahan-bahan (30 porsi)

• 1 stick (1/2 cup butter, softened at room temp)
• 1/2 cup granulated sugar
• 1 egg (room temp)
• 1/2 tsp baking soda
• 1/2 tsp white vinegar
• 2 cups + 2 Tbsp all-purpose flour
• 1 cup jam or thick preserves (I used strawberry spread from Costco)
• Powdered sugar for dusting (optional)