Add milk and butter in a heat proof bowl and microwave for 1 minute. Stir to dissolve the butter and check the temperature with a thermometer to ensure it is below 110°F. Let cool if necessary.
Add a teaspoon of sugar to the warm milk mixture, mix to dissolve. Sprinkle the active dry yeast over the milk and stir to submerge all the yeast. Let it bloom for about 10 - 15 minutes; the mixture should puff up.
In the bowl of your stand mixer, add the rest of the sugar, flour and salt, mix with a whisk to evenly distribute.
Add the bloomed yeast mixture to the flour mixture. Use the dough hook to knead on low speed for 5 minutes. The dough should be soft but not sticky.
Scrape the dough out onto a lightly floured counter top, shape the dough into a ball.
Place dough into an oiled glass bowl, cover with plastic wrap and let rise in a warm spot for 1 - 1.5 hours until at least double in size.
In the mean time, mix together softened butter, brown sugar and cinnamon to make a paste. Set aside until ready to use.
When the dough is ready, scrape it out of the bowl onto a lightly floured counted top and punch the air out. Roll the dough out into a rectangle about 12”x18”.
Spread the cinnamon sugar filling on top of the dough with a spatula as evenly as possible. Sprinkle berries over the filling. Roll it up into a long log.
Cut the log in half, length wise to expose the filling, leaving about 1” uncut at one end. Twist the two strands together by carefully lifting one strand over the other.
Butter a 10” cast iron skillet or similar size round baking pan. Place the roll into the prepared pan in a circle and strategically place the open end on top of the uncut end to cover the doughy part.
Allow the roll to rise for 30 minutes to an hour while the oven preheats to 375°F.
Beat an egg with a tablespoon of water to make egg wash. Brush any exposed part of the dough with egg wash.
Bake in the middle of the oven for 30 - 35 minutes until golden brown.
Remove from the oven and let cool on a wire rack.
Make the maple glaze by whisking together maple syrup with powder sugar. Drizzle all over bread before serving.