Spread butter on one side of each of the 8 slices of bread, and place 4 of them them butter side down on a baking sheet.
8 slices pumpernickel bread, vegan buttery spread
Take about half of the hummus and distribute over the 4 slices of bread.
1 cup hummus
Distribute the sauerkraut over the hummus on each slice.
1 cup sauerkraut
Distribute the avocado slices over the sauerkraut.
For the remaining 4 slices of bread, spread hummus on the side without butter and place hummus side down on the avocado slices.
Bake in the oven for 6-8 minutes, then flip the sandwiches and bake about 6 minutes more, until the sandwiches are golden brown and crispy. (Alternatively, you can grill them on the stove top on a griddle or in a skillet).
I don't usually measure the buttery spread, but I probably use about 1 tablespoon per sandwich.
You can rinse the sauerkraut lightly if it's a little too tart for you. Different brands taste slightly different so I usually try a little before rinsing.
Roasted garlic hummus is also a good variety of hummus to try on this sandwich.
To streamline prep, you can spread all of the hummus on the bottom slice of bread and not bother with doing it in step 6. The reason I do half in step 3 and the other half in step 6 is that the hummus helps to 'glue' the sandwich together, which make for easier flipping in step 7.
You can leave out the avocado altogether if desired, and this sandwich still tastes great!