For the poblano, we want to get the skins to peel off, you can do it over a stove top if you have a gas oven, or in the oven, as below.
Turn on the broiler. Place the poblano pepper on a baking sheet with edges and broil it, flipping it from time to time, until it has black spots and blisters all over, for about 5–7 minutes.
Then, put it in a small bowl, cover it into a plastic bag and loosely seal it, and let it rest for 10 minutes. After it is cool enough to touch, peel the skin off the pepper, take out the seeds, and cut it into thin strips.
Put the strips in a small bowl and mix them with 1 Tbsp. of oil. Add some salt to taste.
For the guacamole:
Mash the avocados with a fork in a medium bowl, then mix in serrano chili, lime juicer, cumin, ½ tsp. lime zest, and remaining 1 Tbsp. oil. Season with salt and pepper.
Thickly spread the guacamole over toast and top with sliced poblano pepper, pumpkin seeds (pepitas), and more lime zest.
