Instructions:
- Preheat oven to 400°F and place a rack in the middle.
- Line a rimmed baking sheet with parchment paper or a silicone mat.
- Generously flour a work surface and place the chilled dough disk on the flour. Dust the top of the dough with flour. Using a rolling pin, roll dough into a circle, turning and flipping the dough as needed with a bench scraper to prevent sticking, until the circle measures 14 inches wide and 1/8 inch thick. Starting at one edge, roll the dough around the rolling pin and transfer to baking sheet. Chill for 30 minutes.
- In a small bowl, combine Kerrygold Skellig Cheese, goat cheese, mayonnaise, chives, and thyme. Taste and season with pepper. Spread the mixture in the center of the chilled dough round, leaving a 1 1/2 inch border. Layer the tomato slices in concentric circles, overlapping slightly, over the cheese mixture. Fold the border up and around the tomatoes, pleating it to make a pretty, circular enclosure leaving the center open. Drizzle a little olive oil over tomatoes and season with salt and pepper. Brush the top of the pleated dough with beaten egg.
- Place galette in the preheated oven and bake until crust is deep golden brown, about 40 to 45 minutes. Use a metal spatula to lift the galette slightly and check the underside of the crust, which should be a beautiful brown color. Transfer to a rack to cool for 15 minutes. To serve, transfer the galette to a serving plate and garnish with basil.