Oat Crêpes with Balsamic Mushrooms and Feta

Steps

1. Make the oat flour first: blend the oats in a blender until fine and powdery.
2. Melt half of the butter and let it cool slightly. Keep the other half for greasing the pan.
3. Add the milk, eggs, melted butter and 2 g of the salt to the blender with the oat flour. Blend until completely smooth, then let the batter rest 20 minutes so the oats hydrate; it should be thin like heavy cream.
4. While the batter rests, make the filling: heat the olive oil in a large skillet over medium-high heat. Add the mushrooms and cook without stirring for 3 minutes, then stir and cook until browned and their liquid has evaporated, about 5 minutes more.
5. Add the red onion and cook 3 minutes until soft. Stir in the garlic and thyme and cook 30 seconds until fragrant.
6. Pour in the balsamic and stir until it glazes the mushrooms. Add the spinach and stir until just wilted. Season with the remaining 1 g of salt and the black pepper, then move the filling to a bowl and wipe out the skillet.
7. Heat the skillet (or an 8-inch nonstick pan) over medium heat and brush it lightly with a little of the remaining butter. Stir the batter, pour in about 1/8 of it, and swirl to coat the pan thinly.
8. Cook the crêpe about 1 minute until the edges lift and the underside is golden, flip, and cook 30 seconds more. Stack on a plate. Repeat with the rest of the batter to make 8 crêpes, brushing the pan with the remaining butter as needed.
9. Lay each crêpe flat, spoon one-eighth of the mushroom filling over half, and sprinkle with one-eighth of the feta. Fold into quarters.
10. Return the filled crêpes to the warm skillet in batches for 1 minute per side, sprinkling the tops with the Parmesan so it melts. Scatter the parsley over the crêpes and serve 2 per person.