Preheat oven to 375°.
Dice the onion and grate the garlic clove.
Heat olive oil on medium heat in a stovetop skillet.
Add the onion and cook for 3 minutes.
Add the spinach and garlic and cook for another 3 minutes.
Remove the skillet from the heat and let it sit for 15 minutes until it is slightly warm or at room temperature.
While the spinach is resting, beat the eggs in a large bowl.
Add the ricotta cheese, parsley, spices, and salt and pepper and mix well.
Crumble 1/2 of the feta cheese into the mixture using your finders and stir it into the egg mixture.
When the spinach is room temperature, stir it into the wet mixture and crumble in 1/2 of the remaining feta cheese. Place the bowl in the refrigerator while you prepare the phyllo layers.
Melt the 4 tablespoons of butter in the microwave.
Open 1 of the sleeves of phyllo dough, roll out the sheets, and cover them with three damp paper towels. Save the second tube for another recipe.
Flip a cookie sheet over, and cover it with parchment paper or a baking mat.
Place 1 phyllo sheet on the cookie sheet, brush the entire sheet with melted butter. Lay the second sheet perpendicular to the first sheet so it's laying crosswise. Brush that entire sheet with butter. Lay the next layer diagonally on top, brush it with butter. Lay the fourth sheet diagonally the other direction and brush it with butter. Continue in this pattern until you have used all of the individual phyllo sheets. (Keep the phyllo sheets covered with the damp paper towels while you are buttering each sheet so they do not dry out.)
Once all of the phyllo is buttered in layers, spoon the spinach mixture in the center of the phyllo sheets, spreading it out and leaving room around the edges to fold over the phyllo dough. Begin by lifting a piece of the phyllo and bringing it to the center while twisting it at the same time. Continue this all the way around the galette.
Brush every piece of phyllo with butter making sure that every open piece of phyllo has been buttered.
Crumble the remaining feta cheese on the top of the exposed spinach area.
Bake the galette at 375° for 25-30 minutes.
Let it cool for 20 minutes before slicing or transferring it to a serving plate.