Heat the olive oil in a large pot over medium-high heat. Once it's shimmering, add your diced onion and cook for about 2 minutes until it starts getting soft and translucent. This builds a flavor base for your entire one pot pasta primavera recipe, so don't rush this step.

Add the minced garlic and stir constantly for 30 seconds—you'll smell it immediately and that's the sign you're doing it right. Don't let it brown or it'll taste bitter, which honestly ruins the whole thing. Keep moving it around in the pan.

Pour in the vegetable broth and crushed tomatoes, then add the oregano, basil, salt, and pepper. Stir everything together and let it come to a gentle boil for about 1 minute. This is when the flavors start mingling together.

Add the uncooked penne pasta directly into the pot—yes, uncooked, that's the magic of one pot pasta recipes. Stir it so the pasta gets coated in the sauce and distributed evenly. Cook for about 12 minutes, stirring occasionally so nothing sticks to the bottom.

After about 10 minutes of cooking, add the frozen mixed vegetables right into the pot. Stir it all together and let everything finish cooking for 2 more minutes. The vegetables thaw in the hot sauce and add so much color.

Check if the pasta is tender and if most of the liquid has been absorbed—mine always sticks a little to the pan and that's totally fine. Taste it and adjust the salt and pepper if you need to. Some people add a splash more broth if it looks too dry, and that's smart.

Remove from heat and stir in the grated Parmesan cheese until it melts into the pasta. Let it sit for 30 seconds so everything comes together, then divide into bowls and serve immediately. This one pot pasta primavera recipe is best enjoyed while it's warm and the cheese is still creamy.