In a mixing bowl combine the teff flour, almond flour, salt, pepper, and Italian seasoning with a whisk.
In a separate small bowl combine the olive oil and the club soda, whisk vigorously for at least 1 minute until the mixture appears creamy and slightly frothy.
Pour the oil and club soda mixture into the flour mixture and stir with a fork to combine until there is no dry flour left (If the mixture seems too dry you can add a tablespoon or two more of club soda, but only if it is necessary.)
The dough at this point will not be in one mass, but instead will appear crumbly, this is exactly what you are looking for.
Pour half of the dough into an ungreased 11 x 7 x 1.125 tart pan with a removable bottom. Gently and evenly press the dough into the tart pan all the way up the edges. When you need more dough to build up the side of the tart pan or to patch a hole simply pour a little more into the pan. Once the tart shell is compete prick the dough all over with a fork.
Bake the tart shell for 12 minutes, some cracking may occur, but this is OK. Allow the shell to cool slightly before continuing.
Grill the veggies
Preheat a grill pan over medium high heat and generously grease the pan with olive oil. In a large bowl whisk together the olive oil, lemon juice, salt, pepper, garlic, and herbs until combined. Toss the sliced vegetables in the marinade until they are completely coated.
Place the veggies in an even layer on the preheated grill pan and allow them to cook until dark grill marks have formed, about 1 1/2 - 2 minutes for smaller slice s more for thicker sliced veggies. Flip and grill the other side until the veggies are tender. Remove from the heat and set aside.
Assemble the tart
Preheat the oven to 350°F. Gently spread 1 cup of hummus into an even layer across the bottom of the tart shell. Chop the grilled onions into small pieces and scatter a layer of the onions over the top of the hummus. Starting at a corner begin alternating the slices of vegetables across the tart, slightly overlapping each row until the onion and hummus layers are completely covered. Sprinkle the lemon zest over the top of the tart and bake for 8-10 minutes to heat the tart through.
Allow to cool slightly, remove from the pan, and slice into pieces to serve.
Notes
You will probably have grilled vegetables left over after building your tart. I usually save them for grilled veggie sandwiches or salad the next day.
