• For the Crust
• In a food processor, add the flour, salt, dried thyme and butter. Pulse the mixture until small pebble-size pieces of butter are visible. Whisk the egg yolk and the cold water together and pulse quickly until the mixture just begins to come together in a ball.
• Transfer the mixture to a lightly floured surface and press into a ball with your hands. Do not knead the pastry dough. Flatten the ball into a smooth disk about 1-1/2 inches thick and wrap it in plastic wrap. Refrigerate for 20-30 minutes

Roll the Dough:

• Return the chilled disk to the flour-dusted work surface and roll lightly with a rolling pin.  If necessary, lift the edges of the dough as you roll using a pastry scraper and re-dust with flour.  Roll the dough into a 14-inch circle about 1/4-inch thick.  
• Roll/wrap the pastry dough around the rolling pin and carefully transfer into the tart pan, fitting it up against the inside edge.  Trim the excess dough from around top of the edge.  Prick the bottom of the crust with a fork and transfer to the freezer for 15-20 minutes.  

Bake the Crust:

• Preheat the oven to 350°F:
• Remove the frozen pastry tart from the freezer.  Spray one side of a large piece of foil with non-stick oil and place it, oil side down, over the pastry.  Press the foil tightly against the frozen pastry molding it to the crust and over the edge.  Fill with pie weights.
• Set the tart pan on a baking sheet, transfer to the oven and bake for 20-minutes.  Remove from the oven and carefully remove the foil with the pie weights.  Let the pastry cool completely before filling.

For the Filling

• Melt two tablespoons of butter in a large skillet. Add the shallots, and cook over medium heat until they are golden brown and slightly caramelized about 10-12 minutes.  Add the garlic and cook for 30 seconds until fragrant, then transfer to a plate and reserve until needed.
• With the skillet over medium-low heat, melt the remaining butter. Add the spinach leaves and cook until wilted, stirring frequently.   Transfer the spinach to a paper towel-lined bowl and press it with the back of a spoon to remove any moisture.
• In a large bowl, whisk together the eggs, cream, milk, salt, and pepper until well combined.  Stir the cheese into the custard.

To Assemble

• Distribute the shallots and garlic over the bottom of the pre-baked pastry crust.  Lay the spinach leaves over the shallots in an even layer.  Place the pan on a rimmed baking sheet and gently pour the egg/cream mixture into the pan, filling almost to the top.  It will puff up as it bakes and then settle as it cools.  Transfer to the center rack of the oven.
• Bake the quiche for 50 to 55 minutes until golden and a small area in the center is still giggly.  Transfer to a wire rack and allow to cool for 30 minutes before slicing.  
• If the quiche begins browning too quickly, lay a sheet of foil over the top of the tart.