In a small bowl, combine the warmed milk (95 to 125°F) with the instant dry yeast and granulated sugar. Stir gently and let it sit for about 5-10 minutes until it becomes frothy.
In a large mixing bowl, combine the melted butter and beaten egg. Once the yeast mixture is frothy, add it to the bowl and mix well to combine all the wet ingredients.
In a separate bowl, whisk together the bread flour, ground cinnamon, and salt (if using). Gradually add the dry ingredients to the wet mixture, stirring with a wooden spoon or spatula until a dough forms.
Transfer the dough to a lightly floured surface. Knead the dough for about 8-10 minutes until it becomes smooth and elastic.
Once the dough is kneaded, gently fold in the heaping cup of raisins until evenly distributed throughout the dough.
Shape the dough into a ball and place it in a lightly greased bowl. Cover it with a kitchen towel and let it rise in a warm spot for about 1 to 1.5 hours, or until it doubles in size.
Once the dough has risen, punch it down to release the air. Transfer it back to a floured surface and shape it into a loaf. Place the loaf into a greased loaf pan.
Cover the loaf again with the kitchen towel and let it rise for another 30-45 minutes until it has puffed up.
While the dough is on its second rise, preheat your oven to 350°F (175°C).
Once the loaf has risen, place it in the preheated oven and bake for 30-35 minutes, or until the top is golden brown and the bread sounds hollow when tapped on the bottom.
Allow the bread to cool in the pan for about 10 minutes before transferring it to a wire rack to cool completely. Slice and enjoy your homemade Raisin Bread!