Preheat your oven to 400F, line two baking sheets with parchment paper and set them aside. Combine flour, ½ teaspoon of salt and ½ teaspoon of sugar in a food processor (hand mixer works fine if you don't have a food processor).

Add butter and mix until the mixture looks crumbly, with the butter the size of small peas. Add 1 tablespoon of water at a time, pulsing until mixture starts to clump together. When you are able to pinch the dough and it holds together, it's done.

Remove dough from the mixer and place on a clean, lightly floured surface. Gently shape and knead the dough into a disk. Don't over do it. You should be able to see little bits of butter through out the dough. Wrap the disk in plastic wrap and refrigerate for half an hour.

Once you've removed all of the skin and seeds, slice it into ¼-inch-thick slices. Put the sliced squash in a large bowl and add the olive oil, minced garlic and thyme. Toss to coat evenly, don't be afraid to stick your hands in the bowl and get a little greasy #SinPena. Spread out the sliced and seasoned squash onto the prepared baking sheets.

Sprinkle the squash with the salt and pepper. Put the unpeeled garlic cloves on the baking sheet and bake until the squash and garlic are tender, about 25-30 minutes. Let those suckers cool down.

Remove the disk from the refrigerator and remove the plastic wrap. Over a lightly floured surface, roll out the dough to a 12-13 inch circle. Make sure your dough is not sticking to the surface, add flour as needed. Transfer to a parchment lined baking sheet.

When the garlic is cool, peel and put in a bowl. Mash with the back of a wooden spoon until smooth and all the cloves have been dismembered.

Cover the butternut squash with a layer of fontina and havarti cheese. Add the remaining butternut squash on top of the cheese layer. Top the butternut squash with the remaining cheese until completely covered.

In a small bowl, combine the egg yolk and tablespoon of water. Whisk the yolk and water until combined. Fold the edges of the pastry toward the center of the galette. Brush the yolk and water mixture over the folded pastry crust, this will make the crust shiny and golden.

Lightly sprinkle coarse sea salt along the prepared crust (optional). Then, pop that sucker in the oven and bake until the crust is crisp and golden, about 25-30 minutes. Let it cool down slightly before stuffing your face slicing and serving.