In a large bowl, add all the ingredients for the dough (warm milk, yeast, sugar, flour, and melted butter). Mix until a shaggy dough forms. Cover and let it sit for 30 minutes.

Knead the dough until it becomes elastic. If it's too sticky, add a tbsp or two of flour. Cover and let the dough rest again.

Punch down the air and gently knead the dough again. Place the dough in a generously oiled baking tray. Cover and let it rise again in a warm spot for about 1-2 hours, or until doubled in size.

Prepare the cinnamon sugar mixture by mixing together melted butter and brown sugar.

When the dough has doubled in size, drizzle a generous amount of melted butter onto the surface. Sprinkle on your cinnamon sugar mixture. Oil your hands, then use your fingers to dimple the surface.

Cover and let the dough rest for 30 minutes while preheating the oven to 400°F.

Bake for 25-30 minutes, or until golden brown.

Prepare the glaze by whisking together powdered sugar and one tbsp of milk at a time until it reaches the desired consistency.

Prepare your cinnamon filling by mixing together the remaining cinnamon, sugar, and melted butter, then add it to a piping bag or a zip lock bag with the end snipped off.

Once the focaccia is done, poke a few small holes into the focaccia, then pipe in the cinnamon filling.

Drizzle on the glaze and spread it over the entire loaf.