Combine basil, lemon juice, and garlic in a food processor. Process until smooth. Gradually pour in olive oil and process until pesto thickens. Add Parmesan cheese, walnuts, and salt; process for 20 seconds more. Refrigerate for 1 hour to allow flavors to combine.

Meanwhile, sprinkle yeast over warm water in a large bowl. Let sit until frothy, about 10 minutes.

Mix flour and salt together in a bowl. Gradually add to the yeast mixture along with olive oil. Stir until just combined. Add more flour if dough is sticking to the sides of the bowl. Turn dough out onto a lightly floured surface and knead until smooth and elastic, about 5 minutes.

Form dough into a ball and place in a lightly oiled bowl. Turn dough over so both top and bottom are oiled. Cover with aluminum foil and let rise until doubled, about 1 hour.

Lightly flour your work surface. Gently stretch and elongate dough into a rectangle roughly 12x18 inches. Spread the pesto over the dough, leaving a 1/2-inch border. Gently roll up into a 'snake', starting from 1 long side. Pinch the seam closed.

Preheat the oven to 425 degrees F (220 degrees C). Dust a baking sheet with cornmeal or line with parchment paper.

Transfer rolled dough onto the prepared baking sheet. Use a pastry cutter or sharp knife to cut the roll in half lengthwise. Turn dough so cut edges face up. Gently crisscross the dough, keeping cut edges facing up. Pinch ends together to form a wreath. Let rest for 30 minutes.

Bake in the preheated oven until golden brown, 20 to 25 minutes. Let cool slightly before serving.