Heat olive oil in a pan over medium heat. Add onion and saute until onions are tender (approx. 7-10 minutes), stirring frequently.
Add jalapeños, garlic, chili powder, salt and pepper to the pan and continue to cook until jalapeños have softened (approx. 2-4 minutes). Remove from heat.
Spread 1-2 tablespoons of cream cheese on each tortilla.
Divide onion mixture between 4 of the tortillas. Top with remaining tortillas (cream cheese side down).
Heat 1/2 teaspoon of butter*** in a pan over medium heat. After it has melted, add 1 quesadilla to the pan. Cook until the bottom is browned and crispy (approx. 2-4 minutes). Flip and cook until the other side is browned and crispy. Remove from the pan.
Add additional butter to the pan and repeat with remaining quesadillas.
Slice and serve immediately.
*My favorite vegan cream cheese brands are Trader Joe's, GoVeggie, Tofutti and Kite Hill.**You could easily swap out the 8 medium tortillas for 4 large tortillas. Rather than placing a second tortilla on top, you will just fold it in half. ***You can add more or less butter depending on your taste. You just want to make sure the tortillas don't stick - plus the butter makes these taste extra yummy!