Dissolve the yeast in the warm water for about 5 minutes.
Meanwhile, whisk together the flour, salt and sugar.
Add the flour mixture to the bowl of a stand mixer fitted with the dough hook.
Turn the mixer on low and pour the water and yeast mixture into the dough. Then, add in the melted butter.
Keep the dough mixing and kneading with the dough hook for about 10 minutes, until a cohesive dough forms.
Stop the mixer. Transfer the dough to the counter and form into a ball.
Oil a clean bowl with olive oil and add the dough ball, turning to coat. Cover the bowl with a clean towel and allow to rise until the dough is doubled in size, about 40 minutes.
Punch down the dough and transfer to a cutting board. Cut the dough into eight equal pieces using a sharp knife.
Form the eight pieces into balls. Cover with a clean towel and allow the balls of dough to rest for 20 minutes.
Line two sheet pans with parchment paper. Stretch each ball of dough into oval-shaped rounds, about 1/2-inch thick. Cover the pans with clean towels and allow to rise for an additional 30 - 60 minutes.
Heat the oven to 400 degrees F, with the racks in the upper and lower third parts of the oven.
Bake the panini breads for 10-12 minutes, rotating the pans halfway through.
Allow the bread to cool before slicing and building your sandwiches.
The breads will keep in an air-tight container or zippered bag for up to 3 days. Or freeze for up to one month.