In the bowl of a stand mixer fitted with the beater attachment, combine the yeast, milk, salt, and sugar. Set aside and allow the yeast to bubble or see some movement. Note: you don't actually have to let instant yeast "activate" but I like to do it anyway. Let's me know I'm set up for success!

Once the yeast is "activated", add the eggs, butter, and vanilla. The batter will look really strange, it will be mostly liquid with tiny little balls of butter. But that's okay! You just want to break things down and combine as much as possible before you add your flour.

Add your flour and continue to mix on medium speed until a soft dough has formed. Make sure that you fluff and scoop your flour when measuring in your cups. You don't want to pack the flour into the measuring cups, or your dough will be too stiff. The dough should be slightly sticky but very workable.

At this stage, you can either remove the dough from the KitchenAid and knead the dough by hand, or you can switch your beater for your dough hook and finish kneading with the mixer.

If you are kneading by hand, I recommend using the folding method, where you stretch the dough away from yourself and then fold back over. Then turn the dough 90 degrees and repeat. Either way you choose to knead your dough, continue kneading until a smooth ball of dough has formed.

Cover the bowl of dough with a kitchen towel and set aside in a warm place to double in size. This will depend on several factors, including the temperature of your kitchen, the temperature of the milk you used, how you chose to knead your dough, etc. but this generally takes about an hour for me. But I keep our house pretty warm! So focus more on the dough doubling in size, and less on the timing. I like to take a picture of the dough before I set it aside so I can compare it to what it looks like later to make sure it has truly doubled.

When you poke the dough and the imprint of your finger mostly remains, but springs back slightly, the dough is ready to be rolled. If the fingerprint fills in quickly and all of the way, let it continue rising. If the fingerprint doesn't spring back at all, the dough is overproofed. You can still continue on with the recipe, but the dough may be a little tougher than you would want.

While the dough is rising, assemble your filling. Combine all of your ingredients into the bowl of your stand mixer with the beater attachment, or in a large bowl using an electric beater.

Beat the filling until it is a thickened, whipped consistency that has lightened in color. The matcha will go from a deep green to a lighter green once it has been whipped up, so keep on beating! Set aside to roll out your dough.

Once your dough has doubled, turn the dough out on a generously floured surface (if you have a nonstick pastry mat like a silpat, this is your moment to use it!)

Flour the surface of the dough and rolling pin, and roll the dough out to a large rectangle. The larger the rectangle, the tighter your spirals will be, so I like to roll it out to at least a 24x16 inch rectangle.

Spread the filling out evenly over the dough using a rubber or offset spatula, making sure to cover out to all of the edges.

Roll the dough as tightly as you can from the wider end. Start off really slowly and work your way across the dough so you can keep your spirals tight.

Then cut into 12 equal size pieces and place in a 9x13 baking dish that has been sprayed with cooking spray or greased with butter.

Cover the rolls with a kitchen towel and allow to proof in a warm spot in your kitchen, until they are double in size, or at least noticeably larger than before. Don't be worried if they don't completely double in size, but you definitely want them to be noticeably larger. This will probably take about 30 minutes to an hour. I promise they will grow even more in the oven!

While the rolls are proofing, preheat the oven to 375F and position a rack to the middle row of your oven.

Once the rolls are finished proofing, prepare the vanilla cream soak by combining the vanilla extract the warmed heavy cream. You can just warm the heavy cream in the oven for about 15 seconds. You just want it to be warm to the touch so that it doesn't stifle the growth of the buns.

Drizzle the cream over the buns and allow the rest of the cream to coat the bottom of the baking dish. This will make them super gooey and add an extra layer of vanilla flavor.

Bake the buns for about 20-25 minutes, or until lightly golden brown on top and cooked through. You can also test that the buns are cooked through by inserting a digital thermometer into the dough of an interior roll - the temperature should be about 188F.

This is an optional set of steps, but I really like the extra layer of the matcha flavor and the extra gooeyness this adds. Complete the glaze while the buns bake.

In a small bowl, whisk together all of the ingredients until fully combined. You want to make sure you whisk until there are no more clumps of powdered sugar or matcha left.

As soon as the buns come out of the oven, pour the glaze evenly over the buns, allowing it to seep into the cracks of the swirls.

As you wait for the sweet rolls to cool, make your Greek yogurt drizzle. Also for good measure, you should probably eat a fresh bun from the oven!

In a small bowl, whisk together all of the ingredients for the drizzle. I kept this really light on the sugar, because I wanted the tanginess from the yogurt to add as a different flavor from the sweetness of the rolls and the bitterness of the matcha. I think it's an amazing combination when you keep the drizzle a little more sour. But you can adjust this to your tastes.

Once the buns have cooled completely, pour the Greek yogurt drizzle over the buns.