How to make Alfajores

Ingredients

• 2 oz unsalted butter
• 1/4 cup sugar
• 1 tsp vanilla powder
• 1 egg yolk
• 1 tbsp water
• 1/2 tsp lemon zest
• 2/3 cup flour
• 1/2 cup corn starch
• 1/2 tsp baking powder
• 1/8 tsp baking soda
• 1/8 tsp salt
• 1/2 cup flour
• 7 oz sweetened condensed milk
• hot water