Preheat your oven to 375 degrees F. Line 2 large baking sheets with parchment paper or silicone baking mats. Set aside.
In a medium bowl, whisk together the flour, cornmeal, baking powder and sea salt.
In another medium bowl, whisk together the olive oil, sugar, eggs, lemon juice and lemon zest until creamy and smooth. Fold the dry ingredients into the wet and mix until a soft dough forms. Do not over-mix.
In 1 tablespoon-sized increments, roll the dough into equal-sized balls. Place them about 2-3 inches apart on the baking sheets.
Bake the cookies for about 14-15 minutes or until the edges are slightly brown. The tops will crack a bit. This is OK. Remove from heat and let the cookies cool on the baking sheets for about 5 minutes before transferring them to wire racks to cool the rest of the way.
For the white chocolate glaze, combine the white chocolate and half and half in a heat-safe glass bowl placed over a barely simmer pot of water to create a double boiler. Make sure the bottom of the bowl does not touch the water. Stir occasionally until the white chocolate is MOSTLY melted, but not all the way. Remove from heat and stir until smooth. Let the glaze cool at room temperature for about 20 minutes, or until slightly thickened.
Dip the the tops of the cookies into the white chocolate glaze. Garnish with fresh thyme. Serve immediately or store the cookies in an airtight container for 3-4 days. Enjoy!