Warm the milk to exactly 110°F using a kitchen thermometer. Dissolve the sugar in the warm milk completely. Sprinkle the yeast on top and give it a gentle stir. Let this mixture sit undisturbed for 5-10 minutes until the surface becomes foamy and bubbly.
In a large mixing bowl, combine the flour, salt, and cinnamon. Whisk these together so the spices distribute evenly throughout.
Pour in the activated yeast mixture along with the softened butter. Using a wooden spoon, start mixing everything together until combined.
Knead the dough for about 8-10 minutes until it feels smooth and elastic. The dough shouldn't stick to your fingers but should feel slightly tacky.
Fold in the raisins during the last minute of kneading, distributing them evenly throughout the dough.
Transfer the dough to a greased bowl and cover it with a clean kitchen towel. Place in the warmest spot in your kitchen and let rise for about 1 hour or until doubled in size.
Turn the dough out onto a surface dusted with cornmeal. Roll the dough to about 1 inch thick. Use a 3-inch round cutter to cut out circles. Gather scraps, re-roll gently, and cut more rounds.
Place each round on a baking sheet generously dusted with cornmeal. Sprinkle more cornmeal on top of each muffin. Let rest for 20-30 minutes to puff up slightly.
Heat a griddle over medium heat. Dust the hot griddle with cornmeal. Carefully transfer a few muffins onto the surface without overcrowding.
Cook for 5-7 minutes per side until golden brown on tops and bottoms while sides stay pale. When you press gently on top, they should feel firm, not squishy.
Remove from griddle and let cool completely before storing. Split in half and toast before serving for best results.