In a large bowl, combine the flour, sourdough starter, ranch seasoning, melted butter and salt. Start by using a wooden spoon, then use your hands to work the dough into a ball. It will start out messy, but once the ingredients blend, it will be a soft and pliable dough. Flatten the ball into a rectangular disc.
Optional: place the dough ball in an air tight small bowl and ferment in the refrigerator for 12 - 48 hours. Then remove from the fridge for 30 minutes before continuing with the next steps.
Using two sheets of parchment paper, sandwich the room temperature dough between the sheets. I put a tea towel or silpat mat under the bottom layer to prevent it from slipping. Roll the dough with a rolling pin until it is about 1/16 of an inch thick. It will nearly touch the edges of the piece of parchment paper when it is thin enough. Thicker crackers or uneven crackers will take longer to bake and could burn on the edges while remaining slightly doughy in the middle.
Preheat the oven to 375°. Prepare the dough by removing then top layer of parchment and drizzling it with olive oil. Smooth the olive oil over the entire surface. I use a pastry brush for this step! Cut the crackers into one inch squares using a knife, pizza cutter, cookie cutters or pastry cutter. Leave the dough exactly as it is, do not try to separate the crackers.
Sprinkle the crackers with coarse salt, pepper and any additional seasonings you desire. I like to sprinkle with a little extra dried dill or parsley.
Bake the sourdough starter crackers for 25-30 minutes. Once they are fully cooked, transfer the crackers to a cooling rack. Do not leave them on the parchment paper to cool, this can cause the bottoms to be soggy.
Store the fully cooled homemade crackers in an airtight container or ziptop bag. These crackers will be fresh for about 3 days, but I've eaten them at a week.