In a large mixing bowl, whisk to combine the flour, instant yeast, sugar, and salt. Set aside.
Warm the milk in the microwave for 20 to 30 seconds, until it is warm, between 105°F and 115°F.
Add the warm milk to the dry ingredients, and mix with a large spoon for 1 minute. (It will still be quite dry). Set aside.
Melt the butter in the microwave at 20 second intervals. Set aside to cool slightly.
In a small bowl, whisk the egg.
Add the melted butter and whisked egg to the dough, and mix until a sticky dough starts to form, after about 1 minute.
Lightly flour a work surface and knead the dough by hand for a full 5 minutes, until it is smooth and elastic. (The dough will be really sticky at first. But after a couple minutes of kneading, it will become more smooth and easier to knead).
Place the dough back in the mixing bowl, and cover it with a damp clean kitchen towel. Leave the dough in a warm place to rise for about 2 hours, until it doubles in size.
Line a 9-inch by 13-inch baking sheet (also called a quarter sheet) with parchment paper or a silicone baking mat. Alternatively, you can use a 9x13 baking dish.
Place the dough inside the baking sheet, and use a rolling pin or your hands to flatten the dough in an even layer all the way to the sides and corners of the baking sheet. Cover with a clean kitchen towel for 20 minutes. Preheat the oven to 350°F. Press your fingers into the dough to form indentations all over.
Cut the cold ¼ cup of butter into ¼-inch cubes, then scatter it all over the top of the dough.
Sprinkle the granulated sugar and cinnamon evenly on top. Evenly sprinkle the sliced almonds on top.
Bake for 18 to 20 minutes, until the cake is golden brown, and a toothpick inserted into the center comes out clean. Allow the cake to cool for 15 minutes. You can use the parchment paper to help slide the cake off the baking sheet and onto a cutting board to slice & serve. Enjoy!!