1Prepare the mushrooms
In a skillet over medium-high heat, heat the olive oil. Add the sliced mushrooms and cook, stirring occasionally, until they are golden brown and have released their liquid (about 5-7 minutes). Season with salt and pepper to taste. Set aside.
2Make the white sauce
In the same skillet over medium heat, melt the butter. Add the minced garlic and cook for 30 seconds until fragrant. Whisk in the flour and cook for about 1 minute, creating a paste. Slowly pour in the milk while whisking continuously to prevent clumps.
3Thicken the sauce
Continue to whisk the sauce until it thickens to a creamy consistency, about 3-5 minutes. Stir in the dried thyme and fresh ground nutmeg. Season with salt and white pepper to taste. Remove from heat.
4Preheat the oven
Place a pizza stone or baking steel in your oven and preheat to 450°F (230°C) for at least 30 minutes.
5Assemble the pizza
On a lightly floured surface, stretch or roll your pizza dough into a 12-inch circle. Transfer the dough to a pizza peel dusted with cornmeal or flour. Spread the white sauce evenly over the dough, leaving a ½-inch border. Distribute the cooked mushrooms evenly over the sauce, then sprinkle with the mozzarella and Parmesan cheeses.
6Bake
Carefully slide the pizza onto the hot stone in the oven. Bake for 10-12 minutes, or until the crust is golden and the cheese is melted and bubbly.
7Finish and serve
Remove from the oven and immediately sprinkle with fresh chives. Let it cool for a couple of minutes before slicing and serving with a glass of Rombauer Pinot Noir.