How to Make It
To prepare the crust, place flours and salt in the bowl of a food processor; pulse until combined.Cut frozen bacon grease into small pieces and add to food processor. Pulse until mixture is crumbly, like wet sand. Add egg and vinegar. Process until mixture comes together, forming a solid mass. Turn out onto a clean dry surface or into a bowl. Form dough into a ball; cover and refrigerate for 1 hour.
Preheat oven to 400°.
Press dough between to pieces of parchment paper. Roll dough into an even, 10-inch round (about ¼ to 1/8 inch-thick). Transfer dough to a greased 9-inch pie pan. Pressing to adhere across the bottom and up the sides. Crimp edges as desired. Bake crust at 400° for 10 minutes; allow crust to cool 15-20 minutes before filling.
To prepare the filling, slice tomatoes ¼ to 1/2-inch-thick. Layer about 1/3 of the tomato slices on top of paper towels and sprinkle with salt. Add more paper towels and another layer of tomatoes; sprinkle with salt. Repeat this process with remaining tomato slices. Let tomatoes stand for at least 1 hour (and up to 12 hours in the refrigerator).
Combine mayonnaise, almond cheddar, nutritional yeast, mustard, herbs, 1 teaspoon salt, black pepper, and eggs in a medium bowl; mix until well combined. You should have about 11/3 cups mayonnaise mixture.
Soon about 1/3 cup of the mayonnaise mixture into the bottom of the cooled crust; spread filling into an even layer. Place 1/3 of the sliced tomatoes on top of the mayonnaise mixture, creating an even layer (tomatoes can overlap slightly). Repeat process layering 1/3 cup mayonnaise mixture and ⅓ of the sliced tomatoes 2 more times, ending the layering with the last 1/3 cup of mayonnaise mixture on top.
Bake assembled pie at 400° for 20-30 mins or until filling is set and golden in color. Check pie during baking and shield the crust if it begins to get too brown. Let pie stand 20 minutes before serving. Garnish with flakey salt, cracked black pepper, and additional fresh basil, if desired.