Preheat oven to 170°F (76.7°C) or preheat oven using "Bread Proof" feature if available.
In a small saucepan add cream, water, butter, brown sugar, vanilla extract and salt. Simmer on low heat just until the butter has melted. Don't let it come to a boil. Set aside to cool for 5 minutes.
In the bowl of a stand mixer with paddle attachment, add half of your measured flour, yeast and lemon zest. On low speed, slowly pour in melted butter mixture until combined. Add in, one egg at a time until all eggs are combined. Scrape down bowl in between if needed. Switch to dough hook, add remaining flour and knead on low or medium low for 10 minutes (not less as gluten needs to develop within this timeframe). Dough should be pliable but not sticky to touch. If too sticky add 1/2 tablespoon of flour and mix until no longer sticky to touch.
Shape dough into a ball and add 1 teaspoon of vegetable oil. Roll dough ball around in bowl to cover with oil. Cover bowl with plastic wrap or a clean tea towel and place into oven. If oven was set to 170°F (76°C), turn oven off and leave door closed (no peeking!). If using bread proof feature, leave oven on. Set timer to 1 hour to proof dough.
In a medium saucepan add blueberries, lemon juice, brown sugar, salt, lemon zest and butter. Bring to a boil on high heat then reduce heat to medium and stir occasionally while blueberries are cooking (10 minutes)
In a small mixing bowl combine cornstarch and water to create slurry. Reduce heat down to medium low and slowly pour in cornstarch slurry. Continuously stir until blueberry compote has thickened. Should resemble thick jam consistency. Set aside to cool ( 15 minutes).
Brush melted butter evenly inside a 9 x 13 inch oven safe bake dish.
Lightly dust a clean surface with flour. Punch down dough in the bowl and roll onto dusted surface. Knead dough for a minute to remove any remaining gas bubbles. With a rolling pin, dusted with flour, roll out dough into a long rectangle shape (approx. 20 inch x 14 inch). The long side of the rolled out dough should be parallel to you. Start with the bottom long side (closest to you), with a spatula, evenly spread the cooled blueberry compote on the surface of the dough, working your way to the sides and forward. Leave a 1 inch gap uncovered along the top long side (this will be the seam to seal once everything is rolled).
Start with the bottom long side, quickly start rolling the dough into a log (tightly), make sure to roll the dough evenly until you reach the top long side. Brush melted butter on the log, then roll it over so that the bottom edge is on the top. Lightly, run your finger along the edge to help seal the log. Brush on melted butter and roll it back so the edge is on the bottom.
With a sharp, large knife, press down and slice the log into 12 even pieces. Place each piece into the baking dish. Brush melted butter on the surface of the buns. Cover with a clean tea towel and let buns rise for 30 minutes. Preheat oven to 350°F (176.7°C) in the meantime.
Remove tea towel and place bake dish on middle oven rack. Bake for 30 to 40 minutes or until buns are golden brown. Remove from oven and allow to cool. (20 minutes)
In a small mixing bowl stir together powdered icing sugar, lemon zest, lemon juice and cream. Pour into a large plastic zipper bag and zip closed. Cut a small piece off the corner of the bag and pipe icing onto buns in diagonal lines. Repeat the diagonal lines in the opposite direction (or swirl the icing on the buns if that's your preference). Enjoy!
Do I use fresh or frozen blueberries?Yes you can. The one thing I will note is that the amount of other berries needed for our recipe may not be the same as blueberries. For example, if you want to substitute with raspberries you may need a little more or less depending on their size. You ultimately want to use about 4.5 cups of berries to make the compote.Can I use other type of berriesYes you can. The one thing I will note is that the amount of other berries needed for our recipe may not be the same as blueberries. For example, if you want to substitute with raspberries you may need a little more or less depending on the size of the berries. You ultimately want to use about 4.5 cups of berries to make the compote.Can I use bottled lemon juice?Technically, yes you can if you don't have fresh lemons on hand. However, when it comes to baking, using fresh ingredients is always best. Bottled lemon juice has additives and preservatives that just don't taste the same as the real lemon juice.How to store and reheat?Left-over buns can be wrapped tightly with plastic wrap and stored in an airtight container. On your counter for 1 to 2 days. In the refrigerator up to 7 days or frozen up to 3 months. To reheat, remove all wrappings and reheat in the microwave for 1 to 2 minutes or until bread is soft again. If still cold or frozen, continue to reheat in microwave with 30 second intervals. If reheating in the oven, set oven temperature to 325°F (163°C) and bake on a tray lined with parchment paper for 5 to 10 minutes or until buns are soft again.