cook pasta according to package directions - reserve 1 cup of the pasta water.
In a medium skillet heat a little olive oil; crumble and brown the sausage and set aside.
In a large skillet add the butter and olive oil, add the garlic, pepper flakes, and a little salt. Cook,stirring occasionally, until the garlic is slightly golden brown, not burned about 2-3 minutes.
add half the Swiss chard and cook down till the leaves are wilted. Add the remaining Swiss chard. the lemon zest and the lemon juice until the leaves are wilted. Remove from the heat.
drain the pasta reserving a cup of the liquid.
Add the pasta and the reserved water, to the Swiss chard,sausage mixture and cook over medium heat for a minute.
Add the grated cheese. Season to taste
spoon into individual bowls. Slice the burrata into cubes. Top pasta with cheese and serve.