Set a 6-qt Instant Pot® to the high saute setting. Add olive oil and sausage. Cook, stirring frequently, until sausage is lightly browned, about 3-5 minutes, making sure to crumble the sausage as it cooks; drain excess fat.
Add onion, and cook, stirring frequently, until translucent, about 3-4 minutes. Stir in garlic and oregano until fragrant, about 1 minute.
Stir in potatoes and chicken broth; season with salt and pepper, to taste.
Select manual setting; adjust pressure to high, and set time for 5 minutes. When finished cooking, quick-release pressure according to manufacturer's directions.
Stir in kale until wilted, about 1-2 minutes.
Stir in half and half until heated through, about 1 minute; season with salt and pepper, to taste.
Serve immediately.
Notes
Use mild or spicy sausage. The sausage is a key ingredient in zuppa toscana. Be sure to use high-quality mild or spicy Italian sausage for authentic flavors, crumbling the sausage until browned.
Russet potatoes serve as a natural thickener. The potatoes will release starch into the broth to create that velvety, restaurant-quality richness. They will also soften under pressure absorbing all the flavors of the broth, becoming extremely tender and "buttery".
Add in leafy greens. This is a great recipe to sneak in leafy greens for those picky eaters. Kale, spinach, collard greens, swiss chard, or arugula are all great options. Always add the leafy greens at the very end to avoid mushy greens.
Finish with half and half or heavy cream. Half and half will yield a lighter version whereas heavy cream will yield a richer, velvety consistency.
Make it dairy-free. Need a dairy free option? Substitute coconut cream or skip the half and half.
Add garnishes. Garnishes are always optional but a fresh sprinkle of grated Parmesan or some crispy bacon will certainly take your soup to the next level, adding more flavor, texture and contrast.
Serve with crusty bread. Serve with all the homemade crusty bread for dipping, sopping and dunking!