• Place 1 cup of flour, sugar, yeast and salt in the bowl of a stand mixer and whisk together.
• In a microwave safe bowl, add butter, water, milk and vanilla and microwave for 30 seconds or just until butter has melted. It should be warm but not hot. If it’s hot, let it cool before adding to flour mixture. Beat on low until combined. Add egg and beat until combined.
• Add 1 ½ cups of flour and beat until combined, then change to the dough hook and beat on low until it is smooth. The dough will be slightly sticky. If it’s too sticky to handle then add more flour. Form into a ball and place in a lightly oiled bowl. Cover and place in a warm place until doubled, about 45 minutes to an hour.
• Punch down the dough to remove the air and roll it into an 8 x 6 inch rectangle and cover with plastic wrap. Refrigerate for at least an hour or overnight.
• Spray a standard 8 x 4 inch loaf pan and line with parchment paper.
• Roll the dough into a 13 x 10 inch rectangle. Spread blueberry sauce over the top, leaving a ½ inch border. Cut dough into four 10 x 3 inch strips and stack them on top of each other.
• Cut strips into 4 equal sections. Stack the sections in the loaf pan starting at the bottom and working to the top. Cover with plastic wrap and let rise in a warm place for about 30 minutes to an hour, until doubled.
• Preheat oven to 350º . Bake uncovered for 15 minutes. Then cover the loaf with foil and bake for 25-30 minutes until it is golden brown. Let cool in the pan for 15 minutes. Remove and drizzle with icing.

Blueberry filling:

• Preheat oven to 400º. Line a rimmed baking sheet with parchment paper.
• Pour melted butter, sugar and lemon zest over blueberries in a medium bowl and stir until they are coated. Place on the baking sheet and bake for 5-10 minutes, until the berries have started to burst but still hold their shape. Let cool completely.

Icing:

• Combine powdered sugar and lemon zest. Add milk and whisk until it is smooth and thin enough to pour over the loaf.