Place basil leaves, pine nuts, garlic, 1/4 cup Parmesan, and salt and pepper to taste in a food processor. Drizzle olive oil through top while running food processor, scraping down the sides as necessary until pesto is smooth. Set aside for a moment.
Roll prepared pie dough out into a 9-in circle. Spread ricotta cheese to within 1-in of edges and top with half of pesto. Arrange cherry tomatoes in the middle.
Gather up edges of dough and fold over tomatoes to create a 1-in border. Brush the crust of galette with egg/water wash and drizzle remaining pesto over tomatoes. Top with remaining 1/4 cup Parmesan cheese.
Bake galette at 400F 30-35 minutes until crust is golden and tomatoes are bubbly. Cool galette at least 10 minutes before slicing into wedges and serving warm. Enjoy!