Lightly grease the bottoms and longer sides of a 9 x 5 loaf pan. Generously grease the shorter ends with butter. Line with parchment paper, leaving about a 2-inch overhang on the longer sides.
In a small bowl, combine the Redpath® Golden Yellow Sugar with the lime zest. With clean fingers or the back of a spoon, rub the zest into the sugar until sugar is moist and fragrant. Set aside to allow flavours to meld.
Layer the stale bread on the bottom of the loaf pan (see Chef’s Tips). Build the layers and slice the bread to size with the undipped, dry bread; assembly will be easier when dipping and building the layers if this is already done. Ensure the slices of bread touching the shorter ends of the loaf pan are sliced or straight to create an even and clean edge.
Remove the sliced bread from the loaf pan in the order it is laid out in the pan and place on a cutting board or platter. The top layer in the pan should now be the bottom layer on the board and vice versa. There should be 4 layers of bread.
In a medium bowl or large measuring cup, whisk together eggs, yolk, vanilla extract, cinnamon, and salt until well combined. Add in the brown sugar mixture and whisk well. While whisking, slowly pour in the half and half. Whisk until mixture is homogeneous and sugar is dissolved. Pour half of the mixture into a dish.
Dip the slices from the bottom layer into the custard, dipping both sides and all edges. Whisk in between dipping slices to ensure zest and cinnamon are evenly distributed.
Lay each piece carefully into the bottom of the loaf pan. Scatter about a third of the blueberries (about 60 grams) and/or haskap berries onto the bread, followed by scattering ¼ of the small butter pieces (about 10 grams) over the blueberries and bread. Repeat process with the remaining bread slices. Level and even out the last layer by gently pressing down on the slices of soaked bread. Whisk together the remaining custard and evenly pour the custard over the entire loaf.
Dot the surface with the last pieces of butter. Cover with foil and place into the fridge to chill and allow the bread to fully absorb the custard; at least 4 hours, but preferably overnight.