Preheat oven to 425 degrees and line a rimmed baking sheet with parchment paper.

Slice large heirloom tomatoes to ¼” thickness, and halve or quarter the smaller tomatoes; arrange all of the tomatoes on the parchment lined baking sheet and season well with salt and pepper. Place tomatoes in the oven for 20 minutes to roast; remove when finished and set aside to cool slightly.

While the tomatoes are cooking, prepare the crust and filling. Roll out two circles of the thawed pie crust dough and layer them on top of one another; use a rolling pin to press them together and create one thick crust to be placed in a deep pie dish. Spread the basil pesto inside the bottom of the crust-lined pie dish and set aside.

To make the filling, stir together egg, mayonnaise, dijon, shredded cheddar, grated parmesan, shallot and garlic. Fold in half of the chives and stir until combined.

Add tomatoes and filling in alternate layers, starting with about ⅓ of the tomatoes, adding half of the filling, another ⅓ of the tomatoes, the remaining half of the filling, and the final ⅓ of the tomatoes on top. Sprinkle with the remaining chopped fresh chives and sprinkle the crust with sea salt.

Bake the pie at 425 degrees for 45 minutes; remove from oven and set aside to rest for 20 minutes before serving.