Combine the flour, baking soda, salt, rosemary, and thyme in the bowl of an upright mixer, fitted with a paddle attachment. Add the butter and mix on low speed until incorporated, about 2 minutes. With the machine running, slowly add the water until the mixture forms a dough, adding more water, if needed, 1 tablespoon at a time. Transfer the dough to a lightly floured work surface and knead for 5 minutes until smooth. Cut the dough into 4 equal pieces. Form into disc shapes and wrap in plastic wrap. Refrigerate for 30 minutes.
Place a grill pan over medium-high heat or preheat a gas or charcoal grill. On a lightly floured work surface, roll out each piece of dough into an 8 to 10-inch circle, about 1/8-inch thick. Brush each circle with olive oil and grill for 4 minutes each side. Remove the flatbread from the grill and cool slightly before serving.