Melt 2 tablespoons vegan butter in a skillet over medium heat. Add the shallots and cook until super tender - approx. 10 minutes, stirring frequently. Add in the spinach and toss until wilted. Remove from the heat and set aside.
On one half of a tortilla, spread 1/2 of the vegan cream cheese and top it with 1/2 of the vegan feta, sun-dried tomatoes & the spinach/shallot mixture. Fold the other half of the tortilla on top of the filling to close it. Gently press down to seal it shut. Repeat with the remaining ingredients to make another quesadilla.
Melt 1 tablespoon of vegan butter in a large skillet over medium heat and add one of the quesadillas. Cook until crispy on both sides - approx. 2 minutes per side. Remove from the skillet, melt the remaining butter and repeat with the remaining quesadilla.