Combine ½ cup olive, parsley, garlic, vinegar, salt, pepper, cumin, oregano, and red pepper flakes into a food processor or blender to make the chimichurri. Pour into a jar and set aside.
Next, set up your grill to medium-high heat.
Toss the bell pepper with 1 tablespoon olive oil in a cast iron skillet and place on the grill. If you don't have a heat proof pan, you can saute the peppers on the stovetop as well. Cook for about 3-4 minutes until slightly charred, then set aside.
Place the brats onto the grill. Cook for approximately 5 minutes on each side, but monitor closely. If browning quickly, the grill is likely to hot. Move the brats to a cooler part of the grill.
After all sides are browned, remove sausages the from the grill and butterfly the sausages lengthwise. Do not slice through the entire sausage.
Return to the grill and sear over high heat for about 2 minutes.
While the brats finish, slice your baguette into 4 equal portions and then slice in half. Place on the grill for 30 seconds - 1 minute to char the bread slightly.
Assemble sandwich with butterflied brat and grilled bell pepper. Top generously with chimichurri.
