Get the meatballs started. Preheat your oven to 450°F. Line a sheet pan with parchment paper and give it a light coating of oil. Toss the diced bread in a large mixing bowl and pour the warm water over it. Let it soak for at least 5 minutes until the bread is fully hydrated and squishy.
In a microwave-safe bowl, combine the butter and minced shallot. Microwave for 30 seconds to 1 minute until the butter melts and the shallot starts turning translucent. This takes the raw edge off and makes everything taste more sophisticated.
Mix the meatballs. Add the ground chicken, parmesan, sage, garlic powder, salt, and that butter-shallot situation to the bowl with the soaked bread. Mix until everything's combined but don't go crazy—overworking makes tough meatballs. Form into about 15 meatballs (roughly 2 oz each), packing them firmly so they hold together. Arrange on your prepared sheet pan, drizzle with a bit more olive oil, and bake on the top rack for 25-30 minutes until they're golden and cooked through.
While the meatballs bake, grab a large skillet and set it over medium heat. Add the butter and let it melt, then toss in the sage leaves. Let them crisp up as the butter starts to brown and smell nutty. Use a slotted spoon to fish out the crispy sage and set it on a paper towel. Keep that brown butter in the pan.
Build the base. Add the sliced shallot to the brown butter with a pinch of salt. Cook for about 2 minutes until it softens. Stir in the orzo and let it toast for a minute. Pour in the white wine and add the thyme bundle. Bring it to a simmer and let it cook for 2 minutes so the wine reduces slightly.
Cook the orzo. Stir in the chicken stock and bring everything back to a simmer. Reduce the heat to medium-low and cook for about 6 minutes, stirring often. The orzo will absorb the liquid and start getting creamy.
Add the heavy cream, spinach, and parmesan. Keep stirring while the cream simmers, the spinach wilts, and the cheese melts into everything. Taste and add salt if needed. Fish out the thyme sprigs.
Spoon the orzo onto plates or into shallow bowls. Top with the meatballs, then garnish with those crispy sage leaves, freshly cracked black pepper, extra parmesan, and any additional fresh sage leaves you've got lying around.