Begin by heating 2 tablespoons of unsalted butter and 2 tablespoons of olive oil in a large pot over medium heat. Once the butter has melted and begun to bubble, add the sliced white and light green parts of 1 leek and 2 minced garlic cloves. Sauté for about 3-4 minutes, stirring frequently, until the leeks are soft and translucent, releasing their sweet aroma.

Next, incorporate 1 diced carrot, 1 medium zucchini chopped into half-moons, and the asparagus tips into the pot. Toss in 1 cup of peas and 1 diced Yukon Gold potato for a creamy texture. Cook these vegetables for about 5 minutes, stirring occasionally, until they start to soften and the colors brighten, signaling their readiness for the next step.

Pour in 4 cups of vegetable broth and bring the mixture to a gentle simmer over medium-high heat. Reduce the heat to medium and let it simmer uncovered for approximately 20 minutes.

Once the vegetables are tender, stir in 1 cup of whole milk, ½ cup of heavy cream, and season generously with salt, black pepper, and 1 teaspoon of dried thyme. Continue to simmer the soup for an additional 5 minutes.

Using an immersion blender, blend the soup until it reaches your desired smoothness; this can take about 1-2 minutes. If you prefer a chunkier texture, blend just until combined.

Finally, stir in freshly chopped dill or chives, along with a splash of freshly squeezed lemon juice to brighten the flavors. Taste and adjust seasoning as needed.